MIEDICAL 


COLLEGE  OF  PHARMACY 


California  College  of  Pharmacy 


WORKS  OF  DR.  H.  W.  SCHIMPF 

PUBLISHED  BT 

JOHN  WILEY  &  SONS,  Inc. 


A  Manual  of  Volumetric  Analysis. 

For  the  use  of  Pharmacists,  Sanitary  and  Food 
Chemists,  as  well  as  for  Students  in  these 
Branches.  Fifth  edition,  rewritten  and  en- 
larged, xx  +725  pages.  6  by  9.  102  figures. 
Cloth,  $4.50  net. 

Essentials  of  Volumetric  Analysis. 

An  introduction  to  the  subject  adapted  to  the 
needs  of  Students  of  Pharmaceutical  Chemistry. 
Third  Edition,  rewritten.  xiii+366  pages. 
SM  by  8.  6 1  figures.  Cloth,  $2.00  net. 

A  Systematic  Course  of  Qualitative  Chemical 
Analysis  of  Inorganic  and  Organic  Sub- 
stances. 

With  Explanatory  Notes.  Third  Edition. 
ix  +  i8?  pages.  6  by  9.  Cloth,  $1.50  net. 


A     SYSTEMATIC     COURSE 


OF 


QUALITATIVE 
CHEMICAL    ANALYSIS 


OP 


INORGANIC  AND  ORGANIC  SUBSTANCES 


WITH  EXPLANATORY  NOTES 


BY         • 

HENRY  W.    SCHIMPF,  Pn.G.,  M.D. 
Professor  of  Analytical  Chemistry  in  the  Brooklyn  College  of  Pharmacy. 

California  College  of  Pharmacy 


THIRD   EDITION,  REVISED 
TOTAL  ISSUE,  FIVE  THOUSAND 


NEW  YORK 

JOHN  WILEY  &  SONS,   INC. 
LONDON:  CHAPMAN  &   HALL,  LIMITED 


CALIFORNIA 

of    PHARMACY 


Authority  to  use  for  comment  the  Pharmacopoeia  of  the  United 
States  of  America,  Eighth  Decennial  Revision,  in  this  volume, 
has  been  granted  by  the  Board  of  Trustees  of  the  United  States 
Pharmacopceial  Convention,  which  Board  of  Trustees  is  in  no  way 
responsible  for  the  accuracy  of  any  translations  of  the  official 
weights  and  measures  or  for  any  statements  as  to  strength  of  official 
preparations. 


COPYRIGHT,  1906,  1917 

BY 
HENRY  W.  SCHIMPF 


PRESS  or 

A  /OQ  BRAUNWORTH   &  CO. 

BOOK    MANUFACTURERS 
BROOKLYN,   N,  Y, 


PREFACE  TO  THE  THIRD  EDITION. 


THE  exhaustion  of  the  second  edition  of  this  book  and  the 
greatly  increased  demand  for  it,  have  encouraged  the  author  to 
publish  a  new  and  revised  edition. 

In  the  latter,  the  features  which  made  the  former  edition 
valuable  to  students  have  been  retained,  but  a  careful  revision 
has  been  made  and  much  new  matter  added.  The  scheme  for 
the  acids  is  greatly  improved  and  many  charts  have  been 
introduced  which  it  is  believed  will  add  to  the  usefulness  of  the 
book. 

The  author  is  very  much  indebted  to  Dr.  Joseph  S.  Goldwag 
for  the  considerable  work  he  has  done  in  the  revision  and  for 
the  introduction  of  many  new  charts  as  well  as  for  his  careful 
proofreading  and  indexing. 

It  is  hoped  that  the  new  edition  will  meet  with  the  same 
generous  appreciation  as  was  accorded  the  former. 

HENRY  W.  SCHIMPF. 


PREFACE  TO  FIRST  EDITION. 


THIS  book  has  been  prepared  for  students  in  pharmacy. 
It  is  based  mainly  upon  the  lectures  on  analytical  chemistry 
and  on  the  hectographed  notes  on  the  laboratory  exercises  which 
have  been  delivered  to  the  students  of  the  Brooklyn  College 
of  Pharmacy  during  the  past  few  years.  When  a  student 
has  but  a  few  months  to  devote  to  the  study  of  analytical 
chemistry  it  is  not  advisable  to  burden  his  mind  by  compelling 
a  study  of  chemical  peculiarities  which  are  prominent  only 
because  of  their  technical  use  in  analysis,  but  rather  to  elimi- 
nate them,  and  direct  his  studies  to  the  more  characteristic 
chemical  reactions.  With  this  in  view  the  author  has  en- 
deavored to  encompass  in  a  small  book  most  of  the  inorganic  as 
well  as  organic  qualitative  reactions  that  a  student  of  pharmacy 
is  required  to  know.  The  first  part  of  the  book  explains  some 
of  the  elementary  principles  of  chemistry,  notation  and  nomen- 
clature, and  prepares  the  student  for  what  follows.  The 
second  part  describes  the  analytical  reactions  of  the  metals 
and  acids  of  pharmaceutical  interest,  and  includes  schemes 
and  tables  for  use  in  analytical  work. 

The  third  part  treats  of  the  qualitative  analytical  reactions 
of  organic  substances,  and  includes  tests  for  official  alkaloids 
and  synthetic  compounds,  as  well  as  other  organic  sub- 
stances used  in  medicine;  also  schemes  for  the  detection  of 


vi  PREFACE. 

poisons,  the  analysis  of  urine,  and  an  article  on  the  prepa- 
ration of  reagents. 

The  final  e  is  dropped  from  the  names  of  halogens  and 
binary  compounds,  but  is  retained  in  the  case  of  the  alkaloids 
so  as  to  avoid  confusing  them  with  glucosides.  Chemical 
equations  are  given  for  most  of  the  reactions  in  the  inorganic 
part  and  for  many  of  the  reactions  of  organic  substances,  as 
it  is  believed  that  they  greatly  assist  in  gaining  a  clearer  insight 
into  chemical  action.  The  author  has  given  credit  in  the 
text  wherever  due,  and  besides  this  he  acknowledges  his  in- 
debtedness to  the  United  States  Pharmacoposia,  Eighth  Decen- 
nial Revision,  and  to  Prof.  Elias  H.  Bartley  and  Dr.  Joseph 
Mayer,  for  their  contributions  and  valued  suggestions;  and  he 
especially  expresses  his  thanks  to  Dr.  I.  V.  Stanley  Stanislaus 
for  the  considerable  work  he  has  done  ^in  the  preparation  of 
this  book. 

H.  W.  S. 

NEW  YORK  CITY,  N.  Y., 
October,  i905. 


CONTENTS. 


PART  I. 

PAGE 

DEFINITIONS  AND  GENERAL  CONSIDERATIONS 1 

Notation,  Classification  and  Nomenclature 7 

PART  II. 

IDENTIFICATION  AND  SEPARATION  OF  INORGANIC  BASES  AND  ACIDS.  .  17 

The  Metals 20 

Group  1 24 

Group  II 30 

Group  III 48 

Group  IV 61 

Group  V 67 

Preparation  of  a  Solution  for  Analysis  in  the  Wet  Way 75 

Alloys  and  Hard  Metals 78 

Table  of  Solubilities 81 

The  Acids 87 

Systematic  Analysis  for  the  Acid 88 

Characteristic  Tests  for  Individual  Acids 91 

Group  A 91 

Group  B 96 

Group  C 106 

Group  D 110 

Group  E 114 

Group  F 121 

Group  G 124 

PART  III. 

QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES 127 

Procedure  for  Detection  of  Ultimate  Constituents  of  Organic 

Substances 12^ 

vii 


viii  CONTENTS. 

PAGE 

Behavior  of  Organic  Substances  with  Immiscible  Solvents 128 

Behavior  of  Organic  Substances  with  Fehling's  Solution 130 

Chart  for  the  Detection  of  the  More  Common  Organic  Com- 
pounds of  Pharmaceutical  Interest 131 

Identification  of  Scaled  Iron  Compounds 154 

A  Scheme  for  the  Detection  of  Poisons 160 

A  Scheme  for  Uranalysis 162 

Preparation  of  Reagents 176 


LIST  OF  CHARTS. 

CHART  SHOWING  EFFECT  OF  GROUP  REAGENTS  ON  THE  METALS 23 

Group  I : 

Comparative  Observation  of  the  Reactions  of  Metals  of. ...  27 

Identification  of  Metal  in  a  Simple  Salt 28 

Synopsis  of  Separation  of 28 

Separation  of 29 

Group  II : 

Comparative  Observation  of  the  Reactions  of  Metals  of ...  39-40 

Identification  of  Metal  in  a  Simple  Salt 41 

Synopsis  of  Separation  of 42 

Separation  of 43 

Group  III: 

Comparative  Observation  of  the  Reactions  of  Metals  of ...  54-55 

Identification  of  Metal  in  a  Simple  Salt 56 

For  "Short  Method"  of  Separation  of  Metal  in  a  Simple 

Salt 57 

Synopsis  of  Separation  of 57 

Separation  of 58 

Group  IV: 

Comparative  Observation  of  the  Reactions  of  Metals  of. ...  64 

Identification  of  Metal  in  a  Simple  Salt 65 

Synopsis  of  Separation  of 65 

Separation  of 66 

Group  V: 

Comparative  Observation  of  the  Reactions  of  Metals  of . . .  71 

Identification  of  Metal  in  a  Simple  Salt 72 

Synopsis  of  Separation  of 72 

Separation  of 73 

Separation  of  Insoluble  Phosphates 75 


CONTENTS.  ix 


PAGE 


Separation  of  Alloys  and  Hard  Metals. 78 

Comparative  Observation  of  the  Reactions  of  Metals  with 

Three  Commonly  used  Reagents 78-80 

Solubilities 81 

Separation  of  a  Solution  into  Groups  of  Metals 82 

Detection  and  Separation  of  a  Mixture  of  Metals  of  the  Five 
Groups 83-86 

Group  A: 

Comparative  Observation  of  Reactions  of  Acids  of 95 

Group  B : 

Comparative  Observation  of  Reactions  of  Acids  of 105 

Group  C . 

Comparative  Observation  of  the  Reaction  of  the  Acids  of . .   109 

Group  D : 

Comparative  Observation  of  the  Reactions  of  the  Acids  of . .   113 
Comparison  of  Gallic,  Tannic  and  Pyrogallic  Acids 117 

Group  E : 

Comparative  Observation  of  the  Reactions  of  the  Acids  of.   119 

Group  F: 

Comparative  Observation  of  the  Reactions  of  the  Acids  of.   123 

Group  G: 

Comparative  Observation  of  the  Reactions  of  the  Acids  of.   126 
Comparison  of  Phenol  and  Creosote 151 


QUALITATIVE   CHEMICAL   ANALYSIS. 


PART  I. 

DEFINITIONS  AND  GENERAL  CONSIDERATIONS. 

1.  Matter. — The    substance  of   which  all  bodies  are   con- 
stituted  is   called    matter.     Examples:    Earth,   wood,   stone, 
air,  vapor,  water,  etc.     There  are  two  kinds  of  matter,  simple 
and  compound. 

Matter  exists  in  three  states  of  aggregation;  i.e.,  as  solids, 
liquids,  and  gases. 

2.  Continuity  of  Matter. — Whenever  a  bar  of  any  metal  is 
heated  it  expands;  when  cooled  it  contracts.     These  changes 
are  most  reasonably  accounted  for  by  assuming  that  the  metal 
is  composed  of  minute  particles  which  are  not  in  absolute 
contact,  and  which  may  approach  or  recede  from  each  other 
with  the  withdrawal  or  application  of  heat. 

This  non-continuity  is  likewise  proved,  when  two  liquids 
of  different  densities  are  mixed;  for  example,  if  50  mils  of 
alcohol  are  mixed  with  50  mils  of  water,  the  product  is  not 
100  mils  of  mixture,  but  only  97  mils,  showing  a  loss  in  volume 
of  3  per  cent.  This  reduction  of  volume  clearly  indicates 
that  between  the  particles  of  one  of  the  two  liquids  there 
must  be  open  spaces  which  particles  of  the  other  liquid  have 
filled  up. 

There  are  many  other  considerations  which  lead  us  to 


2  QUALITATIVE  CHEMICAL  ANALYSIS. 

believe  that  matter  is  not  continuous  as  it  appears  to  the 
senses  and  as  generally  believed,  but  is  composed  of  exceed- 
ingly small  particles  which  are  not  rigidly  joined  together, 
but  are  at  relatively  considerable,  though  exceedingly  minute, 
distances  apart ;  and  that  these  particles  are  in  a  state  of  per- 
petual motion,  which  motion  is  increased  by  raising  and  de- 
creased by  lowering  the  temperature  of  the  mass. 

Matter  is  divided  into  three  general  divisions — masses, 
molecules,  and  atoms;  and  it  is  impenetrable  and  indestructible. 

3.  Mass,  or  body,  is  any  distinct  portion  of  matter  appre- 
ciable by  the  senses. 

Molecules  and  Atoms. — A  molecule  (a  little  mass)  is  "  the 
smallest  particle  of  matter  which  can  exist  in  a  free  state  ". 

The  small  particles  referred  to  in  paragraph  2  are  called 
molecules;  and  masses  of  matter  large  enough  to  be  evident 
to  the  senses  are  aggregations  of  molecules. 

All  compounds  are  made  up  of  one  or  more  distinct  sub- 
stances into  which  they  may  be  split.  Since  every  compound 
can  be  split  into  at  least  two  elements,  it  follows  that  its  mole- 
cule must  consist  of  one  particle  of  each  element.  Hence  there 
must  be  particles  of  matter  smaller  than  the  molecule  itself. 

These  smaller  elementary  particles,  called  atoms,  are  defined 
as  "  the  smallest  particle  of  matter  that  can  enter  a  chemical 
combination".  Atoms  are  the  constituents  of  molecules;  they 
are  indivisible  and  indestructible;  under  ordinary  conditions 
they  cannot  exist  free,  but  when  forced  from  one  combination 
immediately  enter  another. 

A  collection  of  atoms  forms  a  molecule,  and  a  collection  of 
molecules  forms  a  mass. 

The  molecules  of  compounds  may  consist  of  any  number 
of  atoms;  molecules  of  elements  usually  of  only  two. 

4.  Elements  and    Compounds. — As  stated  in  paragraph  1, 
there  are  two  kinds  of  matter,  the  simple  and  the  compound. 

Simple  matter  consists  of  only  one  elementary  substance, 
as  iron,  lead,  oxygen,  carbon.  Compound  matter  is  com- 


DEFINITIONS  AND  GENERAL  CONSIDERATIONS.  3 

posed  of  two  or  more  kinds  of  matter  in  combination,  as  iron 
oxid,  which  consists  of  iron  and  oxygen;  and  lead  sulfate, 
which  consists  of  lead,  sulfur,  and  oxygen. 

Simple  matter  cannot  be  reduced  to  anything  simpler  by  any 
known  means;  it  is  therefore  assumed  to  consist  of  but  one 
kind  of  matter,  and  is  called  an  element. 

About  seventy-four  different  kinds  of  elementary  matter, 
or  so-called  elements,  are  now  known,  and  it  is  almost  certain 
that  others  remain  to  be  discovered.  Out  of  these  elementary 
substances  the  entire  universe  is  constructed. 

The  list  of  compounds,  constantly  increasing,  is  innumer- 
able. 

5.  Definition  of  Chemistry. — Chemistry  is  the  science  which 
considers  the  composition  of  substances  and  changes  of  com- 
position which  they  may  undergo. 

Practically,  the  study  of  chemistry  consists  in  subjecting 
materials  to  the  action  of  certain  substances  called  "  re- 
agents ",  or  to  the  action  of  heat,  light,  or  electricity,  and 
noting  the  changes  which  may  occur.  These  changes  are 
called  "  reactions  ". 

Chemistry  deals  with  the  atoms  composing  the  molecules. 
It  studies  the  properties  of  atoms,  their  association  into 
molecules,  their  mutual  attraction,  the  changes  of  their  posi- 
tions on  the  application  of  various  forces,  the  compounds  they 
form  when  brought  together  with  other  atoms  or  molecules,  etc. 

6.  Inorganic  and  Organic  Chemistry. — By  Inorganic  Chem- 
istry we  mean  "the  study  of  the  compounds  of  mineral  origin  ". 
By  Organic  Chemistry  is  meant  the  study  of  the  compounds 
formed  in  the  tissues  of  plants  or  animals,  and  other  "  organ- 
ized "  compounds.     It  is  usually  defined  as  "  the  chemistry  of 
carbon  compounds  ". 

7.  Chemical    and    Physical    Change.  — Our    knowledge    of 
things  is  derived  mostly  by  observing  their  specific  properties, 
such  as  color,  hardness,  fluidity,  transparency,  odor,  etc.,  and 
the  changes  which  take  place  in  them. 


CALIFORNIA    COLLEGE 
of    PHARMACY 


4  QUALITATIVE  CHEMICAL  ANALYSIS. 

These  changes  are  comprised  under  two  general  headings, 
viz.,  physical  changes  and  chemical  changes. 

A  physical  change  is  one  in  which  the  composition  and 
properties  of  a  substance  are  not  permanently  altered. 

A  chemical  change  is  one  in  which  both  composition  and 
properties  are  permanently  altered  and  one  or  more  new  sub- 
stances produced. 

To  illustrate  the  above-mentioned  changes  we  will  take 
common  salt.  It  is  a  solid;  when  put  into  water  it  dissolves — a 
physical  change  occurs;  now  we  apply  heat,  vaporize  the  water, 
and  recover  the  original  solid — unchanged  common  salt.  If 
we  now  take  the  same  salt  and  dissolve  it  in  sulfuric  acid, 
a  chemical  change  takes  place,  and  the  products  of  this  change, 
hydrochloric  acid  and  sodium  sulfate,  are  entirely  unlike  the 
common  salt  from  which  they  were  formed.  The  acid  and  the 
new  salt  formed  are  new  compounds  produced  by  a  chemical 
change. 

8.  Compounds    and    Mechanical    Mixtures. — These    should 
be  differentiated:    In  a  mechanical  mixture  there  is  no  true 
union  of  the  elements;  in  a  compound  there  is.   As  an  example 
we  will  take  iron  and  sulfur.     Reduce  the  iron  in  a  mortar  to 
the  finest  possible  powder;  do  likewise  with  the  sulfur;  now  mix 
the  powders  intimately  until  the  mixture  presents  a  uniform 
appearance.     Place  a  small  quantity  of  it  under  a  microscope 
and  small  particles  of  iron  and  sulfur  lying  side  by  side  will 
be  revealed. 

Now  if  another  portion  of  the  mixture  is  taken  and  heated 
to  redness,  a  chemical  change  occurs,  a  true  compound  is  formed, 
in  which  neither  the  iron  nor  the  sulfur  can  be  revealed  under 
the  microscope. 

Before  heating,  therefore,  the  powder  was  but  a  mechanical 
mixture,  but  after  heating  a  true  chemical  compound,  iron 
sulfid,  is  found  to  have  been  produced. 

9.  Molecular    Attraction  and  Chemism. — Molecules  attract 
one  another.    When  the  molecules  are  of  the  same  kind  they 


DEFINITIONS  AND  GENERAL  CONSIDERATIONS.  5 

form  a  homogeneous  mass,  and  the  force  acting  between  them  is 
called  cohesion.  When  the  molecules  are  not  of  the  same  kind 
the  force  of  attraction  is  called  adhesion.  A  piece  of  lead 
thrust  into  water  comes  out  wet  because  of  the  water  adhering 
to  it.  Try  now  to  pull  the  lead  apart  to  smaller  pieces:  you 
cannot,  because  cohesion  keeps  it  together.  Chemism  is  to 
molecules  what  cohesion  is  to  masses.  It  is  the  force  which 
attracts  atoms  to  one  another  to  form  molecules. 

10.  Atomic    and    Molecular   Weights. — The   atoms   possess 
definite   weights   of   their   own.     The   atomic  weight   of  any 
element  is  the  number  of  times  its  atom  is  heavier  than  the 
atom  of  hydrogen,  which,  being  the  lightest  substance  known, 
is  generally  used  as  the  standard  of  weight.     Its  atomic  weight 
is  taken  as  one  ;  that  is,  it  weighs  one  microcrith. 

When,  for  example,  oxygen  is  said  to  have  the  weight  of  16, 
it  is  understood  that  its  atom  has  a  weight  of  16  microcriths, 
or  that  it  weighs  16  times  as  much  as  the  hydrogen  atom.  Thus 
we  say  nitrogen  weighs  14,  carbon  12,  sodium  23,  calcium  40, 
etc.  Atomic  weights  are  now  based  on  0  =  16,  which  is  the  stand- 
ard adopted  by  the  International  Committee  on  Atomic  Weights. 

Molecular  weight  is  the  sum  total  of  the  atomic  weights  in 
a  molecule  of  a  substance.  Thus  the  molecular  formula  of  cal- 
cium carbonate  is  CaCOs;  that  is,  it  is  composed  of  one  atom  of 
calcium  having  the  weight  of  40,  one  atom  of  carbon  weighing  12, 
and  three  atoms  of  oxygen  each  weighing  16,  or  48  for  the  three. 
Adding  these  atomic  weights  (40  +  12+48)  together  we  get  the 
sum  of  100,  which  is  the  molecular  weight  of  the  calcium  car- 
bonate, or  common  chalk. 

11.  Valence,    also    called    Quantivalence,    or    "Bonds.*"— By 
the  "  valence  "  of  an  element  is  meant  "  the  combining  power  of 
one  of  its  atoms  as  compared  with  that  of  hydrogen."    As  will 
be  seen,  hydrogen  is  also  the  "  unit  "  of  valence,  as  it  is  of  weight. 

Atoms  of  certain  elements,  such  as  chlorin,  are  found  to  be 
equal  in  combining  power  to  those  of  hydrogen;  i.e.,  one  atom 
of  chlorin  unites  with  one  atom  of  hydrogen.  Hydrogen  being 


6  QUALITATIVE  CHEMICAL  ANALYSIS. 

the  unit  has  the  valency  of  1,  or  one  bond;  it  is  also  called 
a  "monad,"  or  a  "univalent"  element. 

When  it  is  said  that  oxygen  has  the  valency  of  2,  or  that 
oxygen  is  a  dyad,  it  is  meant  that  the  combining  value  of  its 
atoms  is  twice  that  of  the  hydrogen  atom,  and  that  in  order 
to  make  these  two  combine,  two  atoms  of  hydrogen  must  be 


employed  to  satisfy  one  atom  of  oxygen,  thus: 

Nitrogen,  having  the  valence  of  3,  is  a  triad,  and  requires  3 

/H 

atoms  of  hydrogen  to  satisfy  its  atom,  thus:    N^H  =  NH3. 

NH 

From  the  above  we  will  see  that  the  chemical  value  of  any 
atom  is  equal  to  that  of  another  atom  which  can  replace  it 
in  a  molecule.  Thus  atoms  are  divided  into  monads,  dyads, 
triads,  tetrads,  pentads,  hexads,  heptads,  etc.,  according  as  they 
can  replace  1,  2,  3,  4,  5,  6,  or  7  atoms  of  hydrogen  or  its  equiv- 
alent in  a  molecule. 

An  element,  while  it  always  has  the  same  valence  in  the 
same  compound,  may  have  different  valences  in  different  com- 
pounds or  combinations.  In  ammonia  (NH3),  for  example, 
the  valence  of  nitrogen  is  always  3,  but  in  nitrogen  pentoxid 
(N205)  it  is  always  5;  many  other  elements  have  this  variable 
valence. 

A  monad  is  equivalent  to  a  monad. 

1  '  dyad     "         "        .  "  2  monads  or  1  dyad. 

"  triad     "         "        '".3      "       "  1  monad  and  1  dyad. 

"  tetrad  "  "  "  4  "  "  2  dyads  or  1  monad) 

and  1  triad. 

«  '  pentad  "  "  '  l  5  "  "  1  tetrad  and  1  monad, 

"  1  triad  and  2  monads, 
"  2  dyads  and  1  monad. 

The  valence  of  an  atom  is  often  indicated  by  accents  placed 
to  the  right  of  its  symbol,  thus:  H',  H"';  or  by  Latin 
numerals,  as  0",  CIV,  etc. 


DEFINITIONS  AND  GENERAL  CONSIDERATIONS. 


NOTATION,   CLASSIFICATION,   AND    NOMENCLATURE   OP 
ELEMENTS  AND  INORGANIC  COMPOUNDS. 

12.  Symbols. — For  convenience  in  writing  chemical  reac- 
tions and  for  many  other  reasons,  certain  symbols  are  used 
which  represent  or  stand  for  the  names  of  elements.     These 
symbols  are  the  initials  of  their  Latin  names  (H  for  hydrogen, 
0  for  oxygen,  N  for  nitrogen,  S  for  sulfur,  etc.).     When  more 
than  one  element  has  a  name  beginning  with  the  same  letter, 
another  characteristic  letter  is  added.     The  first  letter  is  always 
a  capital,  the  second   is  small  (Hg  for  hydrargyrum,   Os  for 
osmium,  Ni   for  nickel,  Sb  for  stibium,  etc.).      Each  symbol 
stands  for  one  atom  of  the  element,  unless  a  figure  is  attached 
to  the  upper  or  lower  right-hand  corner,  which  indicates  a 
greater  number  of  atoms:  H'  =  l  atom  of  hydrogen,   H2=2 
atoms  of  hydrogen. 

13.  Metals    are     Classified    according    to    their    chemical 
and   physical  relationship.     The   "  Periodic   System "   groups 
the  elements  progressively  in  accordance  with  their  atomic 
weights,  thus  exhibiting  these  relationships  most  perfectly. 

The  arrangement  used  in  this  book  groups  the  elements 
most  advantageously  for  the  practical  work  of  the  chemist. 

The  following  tables  include  the  most  important  elements 
and  acids.  Students  would  do  well  to  study  carefully  and 
commit  to  memory  the  grouping,  symbols,  and  valences. 

In  Table  I  we  will  find  the  Non-Metals  classified.  These 
may  be  solid,  liquid,  or  gaseous  at  ordinary  temperatures. 
They  have  no  lustre,  ductility,  or  malleability,  are  poor  con- 
ductors of  heat  and  electricity,  and  are  electronegative  in 
combinations.  They  are  the  Acid-forming  Elements. 

In  Table  II  we  find  the  Metals,  or  Base-forming  Elements. 
These  are  electropositive,  solid  (except  mercury)  at  ordinary 
temperatures;  generally  heavy  bodies,  good  conductors  of  heat 
and  electricity,  and  possessing  more  or  less  lustre. 


8 


QUALITATIVE  CHEMICAL  ANALYSIS. 


In  Table  III  the  Acids  are  grouped  according  to  their 
valence  or  basicity. 

An  acid  is  denned  as  a  "  salt  of  hydrogen  ".  In  reality 
"  acids  are  the  hydroxids  of  the  non-metals  ",  and  while  not 
all  the  acids  contain  oxygen,  every  acid  contains  hydrogen. 

Acids  containing  oxygen  are  called  oxacids,  of  which  nitric 
acid  (HNOs)  is  an  example ;  those  in  which  oxygen  is  wanting  are 
classed  as  hydracids;  thus  hydrochloric  acid  (HC1)  is  a  hydracid. 

An  acid  consists  of  two  parts :  Replaceable  or  basic  hydrogen, 
and  the  acidulous  radical.  The  hydrogen  may  be  replaced  by 
a  metal,  and  the  acid  radical  may  pass  into  another  compound 
without  splitting  into  its  elements.  The  basicity  or  valence 
of  an  acid  is  determined  by  the  number  of  replaceable  hydrogen 
atoms  it  contains;  thus,  H(C1)  is  a  monobasic  acid,  H2(S04) 
rs  a  dibasic  acid,  H3(P04)  is  a  tribasic  acid,  etc.;  the  acidu- 
lous radicals  are  in  parenthesis. 


14. 


TABLE  I —NON-METALS. 


Grouping. 

Symbol. 

Valences. 

Atomic 
Weights. 

Hydrogen  Group  : 
Hydrogen 

H 

1 

1.008 

Chlorin  Group  : 
Chlorin     .    . 

Cl 

1,  3,  5 

35.46 

Brornin          

Br 

1,  3,  5 

79.92 

lodin        

I 

1,  3,  5 

126.92 

Fluorin 

F 

1 

19.0 

Sulfur  Group  : 
Oxygen        ....        ... 

o 

2 

16. 

Sulfur       

s 

2,  4,  6 

32.07 

Selenium    

Se 

2,  4,  6 

79.2 

Tellurium 

Te 

246 

127.5 

Nitrogen  Group  : 
Boron       

B 

3 

11. 

Nitrogen        

N 

3,  5 

14.01 

Arsenic 

As 

3   5 

74  96 

Antimony 

Sb 

3  5 

120.2 

Phosphorus           

P 

3   5 

31.04 

Carbon  Group  : 
Carbon       

c 

2,  4 

12. 

Silicon      

Si 

2 

28.3 

DEFINITIONS  AND  GENERAL  CONSIDERATIONS. 


15- 


TABLE  II.— THE  METALS. 


Grouping. 

Symbol. 

Valence 
in  -ous 
com- 
pounds. 

Valence 
in  -ic 
com- 
pounds. 

Atomic. 
Weight 

Metals  precipitated,  by 

{  Firf^t  Group  : 

dilute  HC1,  whose  chkrids, 

Silver  

\<r 

1 

107.88 

sulfids,  hydroxids,  and  car- 
bonates   are    insoluble    in 

1      Lead  
I       Mercurosum. 

Pb 
Hg" 

1 

2 

207.1 
200.6 

Metals    precipitated    by 
H2S  in  acid  solution,  whose 

(Second  Group  —  Fir 
Arsenic  

& 

t  Di  i 

As 

ion  : 
3 

5 

74.96 

sulfids      are      soluble      in 

Antimony 

Sb 

3 

5 

120.2 

(NH4)2S. 

I      Tin   ........ 

Sn 

2 

4 

119. 

Second  Group  —  Sec 

ond  Di 

ision  : 

Metals  precipitated  from 

Bismuth  

Pi 

3 

5 

208. 

acid  solution  by  H2S,  whose 
sulfids     are     insoluble     in 

(NH4)2S. 

Copper  
Mercuricum  

Cu 
Hg 

1 

2 
2 

63.57 
200.6 

Cadmium 

Cd 

2 

112.4 

Third  Group  —  First 

Dirisi 

on  : 

Iron      

Fe 

2 

3 

55.84 

Metals  not  precipitated 

Cobalt  

Co 

2 

3 

58.97 

by  H2S  from  acid  solutions 
but    precipitated    by 

1      Nickel  
Manganese  .... 

Ni 

Mn 

2 
2 

3 
3 

58.68 
54.93 

\NH4)2o  as  sulnds. 

[      Zinc        

Zn 

2 

65.37 

Metals  not  preeinitated 
by  H2S  from  acid  solutions 

f  Third  Group  —  Seco 
\      Aluminum  

nd  Di^ 
Ai 

ision  : 

3 

27.10 

but    precipitated    by 

Chromium         .  . 

Cr 

2 

3 

52.0 

(NH4)oS  as  hydroxids. 

Fourth  Group  : 

Metals  not  precipitated 

Calcium 

Ca 

2 

40.07 

by  sulnds,  either  from  acid 
or    alkaline    solution,    but 
precipitated  by  carbonates 

Strontium  
Barium  
[      Magnesium.  .  .  . 

Sr 
Ba 
Mg 

2 
2 
2 

87.63 
137.37 
24.32 

[  Fifth  Group  : 

Lithium  

Li 

1 

6.94 

Metals  not  precipitatec 
by  any  general  reagent. 

•j      Sodium  
Potassium  

Na 
K 

1 
1 

23.0 
39.10 

{      Ammonium.  .  .. 

NH4 

1 

18.04 

10 


QUALITATIVE  CHEMICAL  ANALYSIS. 


16. 


TABLE  III.— THE  ACIDS. 
INORGANIC  HYDRACIDS. 


Name  of  Acid.  Chemical  Formula.  Name  of  its  Salt. 

Monobasic:    Hydrochloric HC1  Chlorid 

' '  Hydrobromic HBr  Bromid 

Hydriodic HI  lodid 

Hydrofluoric.  , HF  Fluorid 

Hydrocyanic HCN  Cyanid 

Dibasic:          Hydrosulfuric H2S  Sulfid 

Tribasic:        Hydroferricyanic H3Fe(CN)6  Ferricyanid 

Tetrabasic:    Hydroferrocyanic H4Fe(CN)6  Ferrocyanid 

INORGANIC  OXACIDS. 

Monobasic:    Chloric HC1O3  Chlorate 

1 1  Bromic HBrO3  Bromate 

' '  lodic HIO3  lodate 

"  Nitrous HNO,  Nitrite 

Nitric HN03  Nitrate 

Dibasic:         Sulfurous H2SO3  Sulfite 

Sulfuric H0SO4  Sulfate 

Thiosulf  uric H2S2O3  Thiosulfate 

Carbonic H2CO3  Carbonate 

Chromic H2CrO4  Chromate 

Tribasic:        Phosphoric H3PO4  Phosphate 

Arsenpus H3AsO3  Arsenite 

Arsenic H3AsO4  Arsenate 

ORGANIC  OXACIDS. 

Monobasic:    Formic BCHO2  Formate 

Acetic HC2H3O2  Acetate 

Lactic HC3H5O3  Lactate 

Benzoic HC7H5O2  Benzoate 

Salicylic HC7H5O3  Salicylate 

Valerianic HC5H9O2  Valerianate 

Dibasic:         Malic H2C4H6O5  Malate 

Oxalic H2C2O4    *  Oxalate 

Succinic H2C4H4O4  Succinate 

"  Tartaric H2C4H4O6  Tartrate 

Tribasic:        Citric H3C6H5O7  Citrate 

"  Meconic H3C7HO7  Meconate 


17.  Importance  of  Symbols.  —  The  symbols  in  Tables  I 
and  II  represent  not  merely  the  name  of  the  element,  but 
also  a  definite  weight  of  the  latter.  Thus  the  symbol  0 
represents  not  merely  oxygen,  but  it  stands  for  one  atom  of 
oxygen  or  16  parts  by  weight;  N  represents  one  atom  of  nitro- 


DEFINITIONS   AND    GENERAL   CONSIDERATIONS.        11 

gen  or  14.01  parts  by  weight;  and  C  represents  12  parts  by 
weight  of  carbon. 

A  Formula  is  an  expression  representing  the  composition  of 
a  molecule ;  it  consists  of  two  or  more  symbols  written  together, 
and  therefore  represents  a  definite  weight,  the  molecular  weight, 
which  is  the  sum  of  the  atomic  weights  of  the  constituent 
atoms. 

Thus  H20  is  the  formula  which  represents  water;  its  molec- 
ular weight  is  18.016,  i.e.,  2.016  parts  by  weight  of  hydrogen 
and  16  parts  by  weight  of  oxygen.  NaCl  is  the  formula  for 
sodium  chlorid,  and  represents  58.46  parts  by  weight  of  sodium 
chlorid;  23  for  the  sodium  and  35.46  for  the  chlorin.  KOH 
is  the  formula  for  potassium  hydroxid,  and  represents  one  atom 
of  potassium,  one  of  oxygen,  and  one  of  hydrogen,  having  the 
weights  39.1,  16,  and  1.008  respectively.  Hence  KOH  repre- 
sents 56.108  parts  by  weight  of  potassium  hydroxid. 

When  we  wish  to  represent  more  than  one  atom,  we  place  a 
small  numeral  at  the  right-hand  lower  corner  of  the  symbol; 
thus  02  represents  2  atoms  of  oxygen,  or  32  parts  by  weight; 
in  the  same  way  K3  =  three  atoms  of  potassium,  B4=four  atoms 
of  boron. 

When  we  wish  to  represent  more  than  one  molecule,  we 
place  a  large  numeral  before  the  formula.  Thus  2KOH  repre- 
sents two  molecules  of  KOH;  the  2  multiplies  each  of  the  atoms 
in  the  molecule.  3H2S04  represents  three  molecules  of  H2S04; 
thus  it  means,  6  XH,  3  XS,  and  12  XO.  The  three  placed  before 
the  molecule  multiplies  the  whole  molecule;  the  smaller  nu- 
merals in  this  case,  2  and  4,  multiply  only  the  atoms  which 
immediately  precede  them;  thus  the  H  is  multiplied  by  2,  and 

the  0  by  4. 

If  a  group  of  symbols  is  inclosed  in  a  parenthesis  and  a 
small  numeral  placed  after  it,  as  in  (NH^  and  (S04)3,  the 
whole  group  is  multiplied  by  the  numeral. 

As  symbols  always  represent  atomic  weights,  so  formulas 
represent  molecular  weights;  thus  the  molecular  weight  of 


12  QUALITATIVE  CHEMICAL  ANALYSIS. 

sodium  sulphate,  Na2S04,  is:    Na2  (23X2)=46,  8  =  32.07,  O4 
(16X4) -64,  which  added  together  give  142.07. 

Equations   are   representations,  by   means   of  symbols,    of 
chemical  reactions.     Example: 

Na2C03         +         2HC1      =      2NaCl    +    H20    +    C02. 

Sodium  Hydrochloric  Sodium  Water.  Carbon 

Carbonate.  Acid.  Chlorid.  Dioxid. 

Na2(23X2)=46         2H=  2.016  2Na  =  46     2H  =  2.016  C  =  12 
C  =12         201  =  70.92      201  =  70.92  0  =  16     02  =  32 

03(16X3)=48 


106  72.936  116.92        18.016         44 

This  equation  indicates  that  sodium  carbonate  treated  with 
hydrochloric  acid  will  yield  sodium  chlorid,  water,  and  carbon 
dioxid.  There  are  one  molecule  of  Na2C03  and  two  molecules 
of  HOI  reacting,  and  producing  two  molecules  of  NaCl  and  one 
molecule  each  of  H20  and  C02. 

Now,  since  symbols  represent  definite  weights,  an  equation 
can  be  easily  reduced  to  figures.  The  atomic  weights  of  the 
elements  entering  into  the  foregoing  equation  are  Na=23, 
0  =  12,  0  =  16,  H  =  1.008,  and  01  =  35.46. 

Thus  we  have  106  parts  of  Na2C03  reacting  with  72.936  parts 
of  HOI  and  forming  116.92  parts  of  NaCl,  18.016  parts  of  H20, 
and  44  parts  of  C02. 

In  an  equation,  the  sum  of  the  atoms  on  one  side  of  the 
sign  of  equality  [  =  ]  should  equal  that  on  the  other. 

18.  Classification  of  Compounds. — Compounds  are  classified 
as  bases,  acids,  and  salts. 

Bases  are  the  hydroxids  of  the  metals.  Slaked  lime  is 
the  commonest  example  of  this  class.  Some  of  the  bases  are 
soluble,  others  not ;  when  soluble  they  have  a  caustic  taste  and 
turn  red  litmus  blue. 

Acids  are  the  salts  of  hydrogen;  these  are  fully  defined  in 
paragrap1!  13  and  classified  in  Table  III.  When  soluble  they 
have  a  sharp,  sour  taste  and  turn  blue  litmus  red. 


DEFINITIONS    AND    GENERAL    CONSIDERATIONS.         13 

Salts  are  acids  in  which  part  or  all  the  basic  hydrogen 
has  been  replaced  by  a  metal;  thus,  if  the  hydrogen  of  sulfuric 
acid  is  replaced  by  potassium,  we  have  formed  a  salt,  called 
potassium  sulfate;  if  the  hydrogen  of  acetic  acid  be  replaced 
by  potassium,  we  have  a  salt  called  potassium  acetate. 

The  salts  are  further  classified  into  normal,  acid,  basic,  and 
double  salts. 

A  normal  salt  is  one  in  which  all  the  basic  hydrogen  has 
been  replaced  by  a  metal,  as  in  Na2COs,  sodium  carbonate. 

An  acid  salt  is  one  in  which  some  of  the  basic  hydrogen  still 
remains,  as  in  NaHCOs,  sodium  acid  carbonate. 

A  basic  salt  is  a  substitution  of  a  metal  in  part  for  the  H  of 
an  acid,  and  in  part  for  the  half  or  the  whole  of  the  H  of  water; 
i.e.,  a  basic  salt  is  a  compound  partly  of  the  nature  of  a  salt  and 
partly  of  the  nature  of  a  hydroxid  or  an  oxid. 

Double  salt  is  one  in  which  the  basic  H  of  an  acid  is  replaced 
by  more  than  one  metal.  Example,  KNaC-jH^Oe. 

The  Names  of  Acids. — All  the  names  of  hydracids  begin  with 
hydro  and  end  in  ic,  as  hydrochloric,  hydroiodic,  hydrobromic, 
etc. 

In  the  oxacids,  the  quantity  of  oxygen  present  in  acids  of  the 
same  element  determines  their  names,  thus:  acids  containing 
the  least  amount  of  oxygen  begin  with  hypo  and  end  in  ous; 
those  containing  the  next  larger  quantity  of  oxygen  end  in 
ous,  omitting  the  hypo;  those  containing  the  next  larger  quan- 
tity of  oxygen  end  in  ic.  If  there  is  a  fourth  acid  containing 
still  more  oxygen  than  the  preceding  one,  its  name  begins  with 
per  and  ends  in  ic.  In  this  way  we  derive  a  table  of  the 
nomenclature  of  the  acids.  Following  is  a  table  of  the  chlorin 
oxacids: 

Formula.  Name  of  Acid. 

HC10  Hypochlorous 

HC102  Chlorous 

HC103  Chloric 

HC104  Perchloric 


14  QUALITATIVE   CHEMICAL  ANALYSIS. 

The  Names  of  Salts. — The  names  of  salts  also  indicate  their 
composition,  both  as  regards  their  constituents  and  the  quanti- 
ties of  these  present  in  them. 

The  names  of  salts  generally  consist  of  two  words,  the  first 
expressing  the  metal,  the  second  expressing  the  acid  radical; 
thus,  sodium  sulfate  =  Na2S04;  zinc  chlorid  =ZnCl2.  The  above 
is  true  only  with  the  normal  salts.  In  the  case  of  acid  or  basic 
salts  three  and  more  words  are  required  to  express  their  name 
and  composition,  as  in  potassium  acid  carbonate,  KHC03, 
etc. 

As  is  seen  in  the  above,  the  prefixes  and  suffixes  employed  in 
expressing  the  names  of  the  acids  and  salts  have  a  very  important 
meaning,  which  the  following  further  explains : 

The  prefix  sesqui  is  used  to  express  a  proportion  of  1  to  1J, 
as  in  Fe203,  iron  sesquioxid.  Prefix  sub,  when  used,  indicates 
a  lower  amount  of  an  element  than  the  name  would  otherwise 
represent;  thus,  Cu20,  copper  suboxid. 

The  prefix  per  or  hyper  or  super  (above)  indicates  the  highest 
of  a  series  of  compounds,  as  contrasted  with  sub  or  hypo,  indi- 
cating lowest.  Examples:  KC104,  potassium  perchlorate; 
Fe2Cl6,  iron  perchlond. 

The  prefix  ortho  (straight)  is  used  to  distinguish  normal  acids 
or  salts.  Example,  H3P04,  or^ophosphoric  acid. 

The  prefix  pyro  (by  fire)  is  used  to  designate  that  the  body  has 
been  produced  by  heat  (fire).  Thus  2H3P04  or  H6P208+heat 
becomes  H4P207,  pyrophosphoric  acid,  water  (H20)  being 
driven  out.  CrHeOs,  gallic  acid,  heated,  becomes  C6H603, 
pyrogallic  acid,  C02  being  driven  out. 

The  prefix  meta  is  used  to  designate  an  altered  condition  as 
distinguished  from  the  ortho  and  pyro  (and  para)  forms.  Thus 
H4P207+heat  becomes  2HP03,  metaphosphoric  acid,  water 
being  driven  out. 

The  prefixes  ortho,  meta,  and  para  (near  to)  are  used  with 
organic  compounds  in  which  some  of  the  constituent  radicals 
are  attached  in  certain  relation  to  each  other;  these  compounds 


DEFINITIONS    AND    GENERAL    CONSIDERATIONS.         15 

have  the  same  chemical  composition  but  differ  in  physical 
properties.  The  following  examples  illustrative  of  this  show  a 
difference  in  the  place  of  attachment  of  the  OH  radicals;  the 
chemical  composition  C6H4(OH)2  being  the  same  in  each. 


OH 


QTT 

is  0r//io-dihydroxybenzol,  or  pyrocatechin. 


is  weta-dihydroxybenzol,  or  resorcin. 

is  para-dihydroxybenzol,  or  hydroquinone. 

OH 

Para  also  indicates  molecular  aggregations  of  certain  organic 
compounds,  as  C2H40  =  aldehyd;  and  (C2H40)3  or  C6Hi203  = 
paraldehyd. 

The  prefix  hydro  indicates  binary  compounds  or  acids,  as 
hydrochloric  acid,  HC1,  fo/oYosulfuric  acid,  H2S,  etc. 

The  prefixes  an  (without)  and  de  (away  from)  are  used  to 
denote  something  which  has  been  removed  from  a  body  in 
which  it  normally  exists.  Examples:  anhydrous,  without  water 
or  moisture;  deodorized,  deprived  of  odor. 

The  nomenclature  of  salts  corresponds  to  that  of  the  acids; 
thus  the  name  of 

a  salt  of  an  hypo  .  . .  ous  acid  begins  with  hypo  and  ends  in  ite 

ous  acid  ends  in  ite 

"  "    ll   lt  ic      (l      "     "  ate 

' '  "    "    a    per  .  .  .  ic     "      begins  with  per  and  ends  in  ate. 

The  following  table  of  the  chlorin  oxacids  with  sodium 
illustrates  this: 

CALIFORNIA    COLLEGE 

of    PHARMACY 


16  QUALITATIVE  CHEMICAL  ANALYSIS. 

Name  of  Acid.  Name  of  the  Salt. 

Hypochlorous  acid  forms  Sodium  Hypochlorite 
Chlorous  "        "  "        Chlorite 

Chloric  "        "  "        Chlorate 

Perchloric  "        "  "        Perchlorate 

For  nomenclature  of  other  salts  see  Table  III.  The  name 
of  a  compound  may  also  be  varied  in  other  ways  to  indicate 
its  composition,  as  di-sodium  phosphate,  Na2HP04,  to  indicate 
that  only  two  atoms  of  basic  hydrogen  in  phosphoric  acid, 
H3P04,  have  been  replaced  by  the  metal.  By  referring  to 
Table  II  we  note  that  many  elements,  as  iron,  bismuth  and 
arsenic,  form  two  or  more  classes  of  compounds  corresponding 
to  their  varied  valences. 

Names  of  these  compounds  in  which  the  element  has  the 
lower  valence  end  in  ous ;  those  in  which  it  has  the  higher  val- 
ence end  in  ic,  as  ferrous  and  ferric  salts,  arsenows  and  arsem'c 
salts,  etc. 

The  names  of  salts  of  all  the  hydracids  end  in  id,  as  will 
be  observed  by  referring  to  Table  III;  so  also  do  the  names 
of  all  other  binary  salts. 

The  terms  binary  and  ternary  salts  designate  those  composed 
of  only  two  or  of  more  elements;  thus,  KC1,  KCN,  etc.,  are 
binary  compounds,  and  KC103,  KSCN,  etc.,  are  ternary  com- 
pounds. 

An  oxid  is  a  compound  formed  by  the  union  of  a  metal  or 
non-metal  with  oxygen.  CaO,  K20,  MgO,  C02,  and  N205. 

An  anhydrid  is  a  compound  left  after  removing  from  an 
acid  all  its  replaceable  hydrogen  and  enough  oxygen  to  form 
water. 

Examples.     H2S04-  H20  =  S03  =sulfuric  anhydrid; 

2H3P04  -  3H20  =  P205  =  phosphoric  anhydrid ; 
H2C03—   H20=  C02= carbonic  anhydrid. 


PART  II. 

IDENTIFICATION  AND  SEPARATION  OF  INORGANIC 
BASES  AND  ACIDS. 

INTRODUCTORY. 

19.  Qualitative  Analysis  has  for  its  object,  the  resolving  of 
more  or  less  complex  substances  into  simpler  ones,  without 
reference  to  the  proportions  or  quantities  of  the  latter  present. 

By  qualitative  analysis  usually  we  mean  the  examina- 
tion of  salts,  i.e.,  combinations  of  bases  and  acids,  the  prob- 
lem involved  in  such  cases  being  the  determination  of  the 
particular  base  and  acid  present  in  the  given  substance.  Thus 
we  examine  a  substance  to  determine  not  directly  what  efo 
ments  are  present,  but  what  metals  and  what  acidulous  radi- 
cals— the  latter  usually  being  groups  of  elements.  For  example, 
in  the  analysis  of  barium  sulfate  we  do  not  search  for  Ba,  S, 
and  0  separately,  but  for  barium  as  the  base  and  S04  as  the 
acidulous  radical. 

In  some  cases  such  as  ammonium  carbonate,  (NH4)2C03, 
where  neither  the  positive  radical  or  base  (NH4)  nor  the  nega- 
tive or  acidulous  radical  (C03)  can  exist  in  the  free  or 
uncombined  state,  we  detect  the  former  by  the  evolution 
of  ammonia-gas  (NH3),  and  the  latter  by  the  expulsion  of 
carbon  dioxid  (C02),  from  the  substance.  The  word  analysis 
is  the  true  antithesis  of  the  word  synthesis;  analysis  mean- 
ing splitting  up  or  breaking  up  of  a  substance,  while  synthesis 
means  the  building  up  of  a  compound  from  its  elements. 

17 


18  QUALITATIVE   CHEMICAL  ANALYSIS. 

Thus  if  we  conduct  an  electric  current  into  a  solution  of  com- 
mon salt,  we  split  the  compound  into  its  components  Na  and 
Cl.  This  process  is  truly  analytical.  If  we  now  bring  sodium 
and  chlorin  together  under  suitable  conditions,  sodium  chlorid 
will  be  formed  in  a  synthetical  way. 

The  word  analysis,  in  chemistry,  bears  a  wide  meaning. 
It  includes  the  manifold  processes  used  by  chemists  in  the 
identification  of  substances.  Thus  substances  are  often  recog- 
nized by  some  characteristic  appearance,  like  a  particular 
crystalline  form,  when  examined  under  a  microscope,  which 
operation  is  known  as  microscopical  analysis.  Often  the  pres- 
ence of  certain  elements  in  a  substance  is  determined  by  exam- 
ining the  light  emitted  when  substances  are  strongly  heated 
in  a  non-luminous  flame  before  an  optical  apparatus  known 
as  a  spectroscope,  in  which  case  the  operation  is  known  as  spec- 
troscopic  analysis.  Again,  the  substance  may  be  examined  in 
a  polariscope  as  to  its  effect  on  light  (much  employed  in  oil 
and  sugar  analysis).  In  this  last  case  the  operation  is  called 
polariscopic  analysis.  The  majority  of  analytical  operations 
depend  on  some  chemical  change  or  reaction.  When  this 
change  occurs  on  strongly  heating  a  substance  and  observ- 
ing its  peculiar  characteristics  in  the  dry  way,  we  call  it  a 
dry  reaction.  Again,  when  such  a  change  occurs  in  the  sub- 
stance in  the  liquid  form,  by  the  action  upon  it  of  another 
liquid  known  as  a  reagent,  we  call  it  a  wet  reaction. 

20.  Reagents,  or  substances  used  to  bring  about  chemical 
changes,  may  be  in  either  the  solid  or  the  liquid  state.  For 
convenience  in  operation  they  are  usually  employed  as  liquids.* 

Reagents  are  divided  into  three  classes: 

General  Reagents,  or  group  reagents,  which  under  certain 
suitable  conditions  react  with  and  precipitate  a  whole  group 
or  class  of  substances  of  similar  character. 

*  Students  should  prepare  their  own  reagents  and  not  be  kept  in  the  dark 
as  to  their  strength;  it  also  gives  them  an  idea  of  the  delicacy  of  many  of  the 
reactions. 


INORGANIC  BASES  AND  ACIDS.  19 

Separatory  Reagents,  by  means  of  which  the  substance  under 
examination  is  separated  from  other  members  of  the  same 
group;  and 

Confirmatory  or  Special  Reagents,  which  are  employed  be- 
cause they  produce  a  certain  peculiar  characteristic  reaction 
with  a  particular  substance  under  examination,  thus  identifying 
it  without  any  further  doubt. 

Reagents,  says  Prof.  Newth,  are  "the  tools  with  which 
the  analyst  works,  and  upon  the  intelligent  and  skilful  use 
of  them  everything  depends." 

To  the  above  a  word  on  the  impurities  in  reagents  may 
be  added.  The  student  should  constantly  bear  in  mind  that 
the  substances  he  is  testing  for  may  be  present  in  the  reagents 
as  impurities.  In  all  such  cases  test  the  reagent  directly,  and 
by  all  means  make  sure  of  its  purity;  it  is  imperative  for  two 
reasons : 

First :  It  precludes  danger  of  serious  errors,  and 

Second:  It  forms  a  habit  of  making  blank  tests  with  re- 
agents and  thus  cultivating  observation  and  logical  reason- 
ing powers. 

In  the  course  of  qualitative  analysis  wet  reactions  are 
thought  the  more  important. 

When  chemical  reaction  takes  place  between  two  or  more 
substances  in  solution,  and  one  of  the  products  of  the  reac- 
tion is  insoluble,  it  is  thrown  out  of  solution  or  precipitated, 
and  is  called  a  precipitate  (abbr.,  ppt.). 

In  these  operations  the  phenomenon  of  precipitation  is 
taken  advantage  of. 

In  precipitation  of  a  substance  the  reagent  should  always  be 
added  gradually,  and  until  no  further  precipitate  forms.  This 
can  be  determined  by  permitting  the  precipitate  to  settle,  or, 
in  case  of  light  and  flocculent  precipitates  which  settle  very 
slowly,  by  filtering  a  little  of  the  liquid  and  adding  to  the  fil- 
trate a  drop  or  two  of  the  reagent. 

In  this  way  we  guard  against  adding  too  much  of  the  reagent, 


COLLEGE 

PHARMACY 


20  QUALITATIVE  CHEMICAL  ANALYSIS. 

which  in  many  cases  partly  dissolves  some  of  the  precipitates 
—a  very  undesirable  thing. 

In  washing  a  precipitate,  one  should  persist  until  the  wash- 
water  will  no  longer  give  a  test  for  any  substance  known  to  be 
present  in  the  filtrate,  for  if  the  precipitate  is  not  thoroughly 
washed,  the  metal  will  be  found  present  in  succeeding  groups, 
which  will  cause  confusion  and  perhaps  error  in  the  analysis. 

Guesswork  will  not  do  in  these  cases;  you  must  be  thorough, 
as  on  the  complete  precipitation  of  the  substances  and  subse- 
quent thorough  washing  of  the  precipitates  the  success  of  the 
analysis  depends. 

THE  METALS 
SEPARATION  OF  GROUPS. 

21.  If  it  were  possible  to  precipitate  by  a  separate  reagent 
each  individual  metal  out  of  a  solution  containing  several  dif- 
ferent metallic  salts,  the  analysis  of  such  a  solution  would  be 
a  very  simple  matter. 

Chemical  analysis  is,  however,  not  so  simple,  for  each 
reagent  will  precipitate  more  than  one  metal,  and  therefore 
in  a  solution  containing  a  large  number  of  metals  the  separa- 
tion must  be  effected  in  groups. 

Thus  assuming  that  we  have  a  solution  containing  twenty- 
four  of  the  more  common  metals  which  we  wish  to  analyze,  the 
procedure  must  be  as  follows: 

22.  Hydrochloric   acid   is  added   to   the  solution  in  slight 
excess.     This  causes  the  precipitation  of  lead,  silver,  and  mercury 
(if  this  is  in  the  form  of  a  mercurous  salt),  as  chlorid.     (The 
Metals  of  Group  I.) 

The  hydrochloric  acid  should  be  added  in  sufficient  quantity  to  pre- 
cipitate all  the  lead,  silver,  and  mercurous  mercury  (mercurosum)  that 
may  be  present  in  the  solution.  To  insure  this,  the  precipitate  is  allowed 
to  settle,  and  the  clear  liquid  above  it  treated  with  a  few  drops  more  of 
hydrochloric  acid.  If  this  fails  to  produce  a  precipitate,  the  acid  has  been 
added  in  sufficient  quantity.  If,  however,  a  precipitate  is  produced,  more 
hydrochloric  acid  must  be  added.  A  large  excess,  however,  is  to  be  avoided. 


INORGANIC  BASES  AND  ACIDS.  21 

N.B.  Bismuth  and  antimony  are  precipitated  by  diluted  hydrochloric 
acid,  in  the  form  of  oxychlorids.  Such  a  precipitate  must  not  be  mistaken 
for  that  of  the  metal  3  of  Group  I. 

23.  Having  precipitated  the  metals  of  Group  I  as  above 
described,  allow  the  precipitate  to  settle,  and  pass  the  super- 
natant liquid  through  a  filter.     This  solution,  which  contains 
the  remaining  twenty-one  metals,  is  treated  with  excess,  of  the 
Group  II  reagent,  namely,  hydrogen  sulfid  (H2S).    This  causes 
the  separation  of  seven  more  metals,  namely,  mercury  in  mercuric 
salts  (mercuricum) ,  copper,  bismuth,  cadmium,  arsenic,  anti- 
mony, and  tin,  in  the  form  of  sulfids.     (The  metals  of  Group  1 1.) 

These  metals  take  up  the  sulfur  from  the  hydrogen  sulfid  and  form  in- 
soluble sulfids.  In  color  the  sulfids  of  mercury,  copper,  and  bismuth  so 
precipitated  are  black,  cadmium  and  arsenic  yellow,  antimony  orange, 
and  tin  brown  or  yellow. 

The  hydrogen  sulfid  is  best  used  in  the  form  of  the  pure  gas,  which 
should  be  allowed  to  bubble  through  the  solution  until  the  latter  is  thoroughly 
saturated.  A  saturated  aqueous  solution  of  the  gas  is  sometimes  used 
instead  of  the  gas  itself. 

24.  Having  precipitated  the  metals  of  Group  II,  separate  the 
precipitate  by  filtration.     The  filtrate  now  contains  only  four- 
teen metals.     To  this  filtrate  is  added  ammonium  chlorid,  about 
J  its  volume,  and  ammonium  hydroxid  in  sufficient  quantity 
to  render  the  solution  alkaline,  then  a  slight  excess  of  ammonium 
sulfid.      Another  separation  of  seven  metals  will  take  place, 
namely,  iron,  zinc,  aluminum,  manganese,  chromium,  cobalt,  and 
nickel,  as  sulfids  except  aluminum  and  chromium,  which  sep- 
arate as  hydroxids.     (The  Metals  of  Group  III.) 

The  sulfur  of  the  ammonium  sulfid  unites  with  the  metals,  iron,  zinc, 
manganese  cobalt,  and  nickel  forming  sulfids  of  these  metals,  but  chrom- 
ium and  aluminum  are  precipitated  as  hydroxids.  In  color  the  precipitates 
produced  with  iron,  cobalt,  and  nickel  are  black,  with  manganese  flesh 
color,  with  zinc  and  aluminum  white,  and  with  chromium  pale  greenish. 

25.  Having  added  sufficient  of  the  ammonium  sulfid  (the 
Group  III  reagent)  to  completely  precipitate  the  metals,  the 


22  QUALITATIVE  CHEMICAL  ANALYSIS. 

mixture  is  again  filtered  in  order  to  separate  the  precipi- 
tate. 

26.  If  now  to  the  filtrate,  in  which  only  seven  metals  are  left, 
an  excess  of  ammonium  carbonate  solution  be  added,  the  metals 
barium,  calcium,  and  strontium  are  precipitated  in  the  form 
of  carbonates  (Group  77),  leaving  in  solution  magnesium, 
potassium,  sodium,  ammonium,  and  lithium.  (Group  V.) 

From  this  solution  the  magnesium  may  be  precipitated 
by  adding  sodium  phosphate. 

Since  much  ammonium  has  been  added  in  the  course  of  the 
analysis,  a  special  test  must  be  made  for  it  in  the  original 
solution. 

Each  group  of  metals  separated  as  above  described,  is 
further  separated  into  its  component  metals  according  to  the 
charts,  and  each  metal  identified  by  characteristic  tests. 

These  tests  in  most  instances  cannot  be  applied  satisfac- 
torily unless  upon  solutions  of  single  metals. 


INORGANIC  BASES  AND  ACIDS. 


23 


27.  CHART  SHOWING  THE  EFFECT  OF  THE  GROUP  REAGENTS 
ON  THE  METALS 


Group  I. 

Group  II. 

Group  III. 

Group  IV. 

Group  V. 

HC1 

H2S 

NH4OH 

(NH4)2S 

(NH4)2CO3 

No  Group 

in  slight 

in  presence  of 

in 

in 

in 

reagent. 

excess. 

HC1. 

presence 

presence 

presence 

of  NH4C1 

ofNH4OH 

ofNH4OH 

and 

and 

NH4C1. 

NH4C1. 

Na2HPO4 

Pb 

Pb 

Fe  (ous) 

Zn 

Ba 

Mg 

K 

White 

Black  ppt. 

Greenish 

White 

White 

White 

ppt. 

ppt. 

ppt. 

ppt. 

ppt. 

Hg"  (ic) 

Fe  (ic) 

Black  ppt. 

Brown 

X 

ppt. 

Na 

Ag 

w 

Mn 

White 

fc 

Flesh-col- 

ppt. 

ored  ppt. 

(curdy) 

Bi 

rS 

/-\ 

Cr 

Sr 

Blackish- 

•9 

Greenish 

White 

brown 

1 

ppt. 

ppt. 

ppt. 

c 
t—  1 

Hg'  (ous) 
White 

Cu 

Al 

Li 

ppt. 

Black  ppt. 

White 
ppt. 

Co 

NIL 

Black 

Ca 

Cd 

ppt. 

White 

Yellow  ppt. 

ppt. 

As 

Ni 

Yellow  ppt. 

s 

Black 

ppt. 

Sb 

w 

Orange  ppt. 

£ 

.  fl 

Sn  (ous) 

<u 

Brown  ppt. 

3 

3 

Sn  (ic) 

1 

Yellow  ppt.  , 

24  QUALITATIVE  CHEMICAL  ANALYSIS. 

SPECIAL  TESTS  FOR  METALS  OF  GROUP  I. 

(CHLORID  GROUP.) 

Each  of  these  tests  should  be  applied  to  a  fresh  portion  of 
the  original  solution. 

28.  Lead. 

(Make  test  on  a  solution  of  Lead  Nitrate.) 

1.  Precipitated  by  HCl=a  white  crystalline  precipitate  of 
PbCl2  soluble  in  hot  water: 

Pb(N03)2+2HCl  =PbCl2+2HN03. 

Plumbic  Chlorid. 

2.  The  lodid   Test:    KI   gives  a   crystalline   yellow  ppt., 
PbI2,  soluble  in  hot  water: 

Pb(N03)2  +2KI «  PbI2  +2KN03. 

Lead  lodid. 

3.  The  Chromate  Test:    K2Cr04  gives  a  bright-yellow  ppt., 
PbO04,  soluble  in  NaOH: 

Pb(N03)2  +K2Cr04  =  PbCr04  +2KN03. 

Lead  Chromate. 

4.  The  Sulfuric   Acid   Test:    H2S04  gives  a  white   ppt., 
PbS04,  soluble  in  NaOH : 

Pb(N03)2  +H2S04  =  PbS04  +2HN03. 

Lead  Sulfate. 

5.  The  Ammonia  Test:  NH4OH  gives  a  white  ppt.  (basic  salt). 
3Pb  (N03)  2 +4NH4OH = 2PbO  •  Pb  (N03)2 + 4NH4N03 +2H20. 


COLL 

RMA^ 

INORGANIC  BASES  AND  ACIDS.  25 

29.  Silver. 

(Make  tests  on  a  solution  of  Silver  Nitrate). 
6.  Precipitated  by  HC1  =  a  white  ppt.  AgCl,  soluble  in  NH4OH; 
reprecipitated  by  HN03: 

AgN03  +HC1  =  AgCl  +HN03. 

Silver  Chlorid 

7.  Ammonia  Test. — NH4OH=a  brownish-gray  ppt.,  Ag20, 
soluble  in  excess: 

2AgN03  +2NH4OH  -  Ag20  +2NH4N03  +H20, 

Silver  Oxid. 

8.  Chromate    Test. — K2Cr04  =  a   brick-red  ppt.,  Ag2Cr04, 
soluble  in  NH4OH: 

2AgN03  +K2Cr04  -  Ag2Cr04  +2KN03. 

Silver  Chromate. 

9.  lodid  Test. — KI  =  a  pale-yellow  ppt.,  Agl,  insoluble  in 


AgN03  +KI  =  Agl  +KN03. 

Silver  lodid. 


30.  Mercurous  Salts. 

(Make  tests  on  a  solution  of  Mercurous  Nitrate.) 

10.  Precipitated  by  HCl  =  a  white  ppt.,  Hg2Cl2,  blackened  by 
NH4OH: 

Hg2  (N03)  2 + 2HC1 = Hg2Cl2  +  2HN03. 

Mercuroua  Chlorid. 


26  QUALITATIVE  CHEMICAL  ANALYSIS. 

11.  lodid  Test. — KI  =  a  greenish-yellow  ppt.  of  Hg2l2: 

Hg2(N03)2  +  2KI  =  Hg2I2  +  2KN03. 

Mercurous  lodid. 

12.  Ammonia    Test. — NH4OH  =  a    black    ppt.    insoluble    in 
excess : 

Hg2(N03)2  +  2NH4OH  =  NH2Hg2N03  +  NH4N03  +  2H20. 

Mercurous  Ammonium  Nitrate. 

13.  Chromate  Test.— K2Cr04=red  ppt.  of  Hg2Cr04. 

Hg2(N03)2  + K2Cr04 = Hg2Cr04 + 2KN03. 


INORGANIC  BASES  AND  ACIDS. 


27 


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28 


QUALITATIVE  CHEMICAL  ANALYSIS. 


32.    CHART  FOR  THE  IDENTIFICATION  OF  THE  METALS  OF 
GROUP  I  IN  A  SIMPLE  SALT. 


Group. 

Reagent. 

Result. 

Indication. 

Confirmatory  Tests  which  Should 
be  Applied  to  Original  Solution. 

I 

To  a  por- 
tion    of 
original 
solution, 
add  HC1, 
drop  by 
drop  un- 
til no 
further 
ppt  . 
falls. 

White  ppt. 
soluble 
in    hot 
H2O. 

Pb 

Add  KI=  yellow  ppt. 
Apply  tests  as  under  para- 
graph 28. 

White 
ppt.  sol- 
uble   in 
NH4OH. 

Ag 

Add    K2CrO4  =  brick-red 
PPt. 
Apply     tests     under     para- 
graph 29. 

White 
ppt. 
t  u  r  n  ed 
black  by 
NH4OH. 

Hg 

Add    KI  =  greenish-yellow 
ppt. 
Apply  tests  under  paragraph 
30. 

33.  In  the  following  chart  as  in  fact  in  all  analyses  of  solu- 
tions containing  more  than  one  metal  the  student  should 
remember  that  he  must  precipitate  all  the  metals  of  the  group 
from  the  original  solution  by  means  of  the  proper  group  reagent, 
and  then  separate  the  precipitated  metals  one  from  the  other  in 
the  manner  described,  before  any  attempt  at  identity  be  made. 

He  must  not  test  for  a  particular  metal  by  any  particular 
reagent  in  the  original  solution,  except  in  the  case  of  the  alkali 
metals. 

It  would,  for  instance,  be  quite  improper  and  unsatisfactory 
to  test  for  silver  in  the  presence  of  lead  and  mercury  by  means  of 
the  iodid  or  the  chromate  reagents,  as  these  act  upon  all  three 
metals  and  give  a  different  colored  precipitate  with  each. 


34- 


SYNOPSIS  OF  SEPARATION  OF  GROUP  I. 


P.O.S.+HC1 

=  ppt.  =PbCl2+AgCH-Hg2Cl2 

+hot  H2O 

=  dissolvesPbC!2 
Ppt.=AgCl+Hg2Cl2 

+NH4OH 

=  dissolves           AgCl 
ppt.  black  =  Hg2Cl2 

INORGANIC  BASES  AND  ACIDS. 


29 


35-    CHART   FOR  THE  SEPARATION  OF  GROUP  I. 

Group  Reagent :  Dilute  hydrochloric  acid. 

To  a  portion  of  the  original  cold  solution  add  dilute  HC1  drop  by  drop 
as  long  as  a  precipitate  forms,  then  add  a  little  more,  agitate  and  filter. 
Reserve  filtrate  for  Group  II  and  examine  the  precipitate  as  below. 

1.*    GROUP  I.     PRECIPITATE. 
May  contain  Pb,  Ag,  or  Hg'  (ous). 

Wash  this  precipitate  with  cold  water,  till  the  washings  are  free  from 
HC1  (when  the  washings  will  give  no  precipitate  with  AgNO3),  and  reject 
the  washings.  Then  pour  much  hot  water  on  the  ppt.  and  collect  the  hot 
solution.  


2.  Filtrate   may   con- 
tain Pb. 


3.  Divide  the  filtrate 
into  three  portions  and 
test  as  follows: 

1.  H2SO4  =  white  ppt. 

2.  Kl —yellow  ppt. 

3.  K2CrO4  =  orange  ppt. 


i  4.  Ppt.  on  filter  paper  may  contain  Ag  and 
Hg(ows).  Pour  upon  it  some  warm  NH4OH 
and  collect  the  fiKrate. 


5.  Filtrate  may 
contain  Ag. 

Confirm  by  add- 
ing HNO3=  white 
ppt. 


6.  Ppt.  on  filter  paper 
may  contain  Hg  (ous).  -If 
the  ppt.  turns  black  on 
addition  of  the  NH4OH  in 
step  4,  it  indicates  Hg(ows) . 
Confirm  by  dissolving  in 
aqua  regia  (3  parts  HC1 
and  1  part  HNO3);  dilute 
with  water  and  add  SnCl2 
=  grayish  ppt. 


*  The  numbers  refer  to  the  notes.     The  student  should  read  the  notes 
as  he  performs  each  step,  as  they  explain  the  reasons  for  each  method  used. 


36. 


NOTES  ON  GROUP  I. 


(1)  On  the  addition  of  HC1  the  following  chlorids  are  formed: 
lead  chlorid  (PbCl2),  silver  chlorid  (AgCl),  and  mercurous 
chloric!  (HgCl).  These  being  insoluble  are  precipitated  together 
with  the  oxychlorids  of  antimony  (SbOCl)  and  bismuth  (BiOClj. 
The  first  three  are  insoluble  in  weak  acids;  the  remaining  two 
are  soluble  in  excess  of  weak  acids  and  water,  therefore  remain 
in  the  filtrate.  Lead  chlorid  is  slightly  soluble  in  water,  and 
when  present  in  mere  traces  only,  it  passes  into  Group  II, 
where  it  precipitates  as  sulfid. 


CALIFORNIA   COLLEGE 

of   PHARMACY 


30  QUALITATIVE   CHEMICAL  ANALYSIS. 

It  is  advisable  to  use  dilute  HC1  for  the  following  reasons: 

(a)  Strong  HC1  precipitates  various  other  salts  from,  strong 
solutions. 

(&)  AgCl  and  HgCl  are  to  some  extent  soluble  in  strong 
HC1 ;  traces  of  these  might  therefore  be  overlooked. 

(c)  The  BiOCl  and  SbOCl  are  soluble  in  HC1,  and  hence 
pass  over  into  Group  II. 

(2)  When   boiling   H20    is  poured   over    the   precipitate, 
the  lead  chlorid  being  soluble  passes  through  the  filter  and 
deposits  on  cooling. 

The  presence  of  lead  in  the  filtrate  may  be  proven  by  divid- 
ing it  into  three  portions,  and  tests  applied  to  each  portion. 
See  par.  28. 

(3)  When  solution  of  NH4OH  is  poured  over  the  precipi- 
tate left  on  filter,  the  AgCl  dissolves,  forming  argentic  amin, 
AgCl(NH3)2. 

(4)  The  insoluble  ppt.  left  on  the  filter  is  the  black  mer- 
curous  amin,  NH2Hg2Cl,  which  is  rather  unstable  and  yields 
some  metallic  mercury  by  decomposition. 

The  Hg"  may  also  be  proven  by  mixing  some  of  the  black 
precipitate  with  dry  Na2C03  and  heating  in  a  tube,  when 
metallic  globules  or  a  mirror  of  mercury  will  be  formed. 

When  aqua  regia  is  poured  over  the  precipitate  it  forms 
mercuric  chlorid  (HgCl2),  which  is  reduced  by  stannous  chlorid 
(SnCl2)  to  grayish-white  mercurous  chlorid  (Hg2Cl2)  or  black- 
ish-gray metallic  mercury  (Hg). 

(5)  The  addition  of  the  HN03  in  the  confirmatory  test 
neutralizes  the  ammonia,  and  the  AgCl  is  thrown  down  as  a 
white  curdy  precipitate. 

SPECIAL  TESTS  FOR  METALS  OF  GROUP  II. 
(AciD  SULFID  GROUP.) 

Each  test  to  be  made  upon  a  fresh  portion  of  the  original 
solution. 


A    COLUGE 
ot    HHAHMACX 

INORGANIC  BASES  AND  ACIDS  31 

37.  Mercuricum. 

(Make  tests  on  a  solution  of  Mercuric  Chlorid.) 

14.  Precipitated  from  acid  solution  by  H2S  =  a  reddish-black 
ppt.  of  HgS,  insoluble  in  HN03: 

HgCl2+H2S  =  HgS+2HCl. 

Mercuric 
Sulfid. 

15.  Sodium  Hydroxid  Test. — NaOH  =  a  yellow  ppt.  of  mer- 
curic oxid,  HgO,  insoluble  in  excess: 

HgCl2  +2NaOH  =  HgO  +2NaCl +H20. 

Mercuric 
Oxid. 

16.  Potassium  Iodid  Test. — KI=a  red  ppt.  of  mercuric  iodid, 
HgI2,  soluble  in  excess  of  KI  and  HgCl2: 

HgCl2  +2KI  =  HgI2  +2KC1. 

Mercuric 
Iodid. 

17.  Ammonia  Test.— NH4OH  =  a  white    ppt.   of    mercuric 
ammonium  chlorid,  NH2HgCl: 

HgCl2  +2NH4OH  =  NH2HgCl  +NH4C1 +2H20. 

Mercuric  Am- 
monium Chlorid. 

18.  Chromate  Test. — K2O04=a  reddish-yellow  ppt.  of  mer- 
curic chromate  HgCr04,  soluble  in  HNOs. 

HgCl2  +  K2Cr04 = HgCr04 + 2KC1. 


32  QUALITATIVE  CHEMICAL  ANALYSIS. 

38.  Bismuth. 

(Make  tests  on  a  solution  of  Bismuth  Nitrate.) 

19.  H2S  in  acid  solution  =  a  brown  ppt.  of  Bi2S3,  insoluble 
in  (NH4)2S: 

2Bi(N03)3 + 3H2S = Bi2S3  +  6HN03. 

Bismuth  Sulfid. 

20.  Potassium  lodid  Test. — KI  =  a  greenish-brown  ppt.  of 
BiI3,  soluble  in  excess: 

Bi(N03)3  +3KI  =  BiI3 + 3KN03. 

Bismuth  lodid. 

21.  ChromateTest.— K2Cr04=a  yellow  ppt.  of  Bi2(Cr04)3: 


Bismuth  Chromate. 

22.  Water  Test. — Acidify  with  HC1,  evaporate  to  a  small  bulk 
in  test  tube,  and  then  pour  into  a  large  volume  of  water.    A 
milkiness  indicates  bismuth: 

BiCl3 + H20  =  BiOCl + 2HC1. 

39-  Copper. 

(Make  tests  on  a  solution  of  Copper  Sulphate.) 

23.  Precipitated  from  acid  solutions  by  H2S  =  a  brownish- 
black  ppt.  of  CuS,  soluble  in  HN03: 

CuS04 + H2S = CuS + H2S04. 

Copper  Sulfid. 

24.  Ammonia  Test. — NH4OH  =  a  blue  ppt.  soluble  in  excess 
to  a  dark-blue  liquid: 

CuS04+2NH4OH  =  Cu(OH)2  +  (NH4)2S04 
and 

CuS04 +4NH4OH  =  Cu(NH4)2(NH2)2S04+4H20. 

Ammomo-cupric  Sulfate. 


INORGANIC  BASES  AND  ACIDS.  33 

25.  Sodium  Hydroxid  Test. — NaOH  =  a  blue  ppt.,  becoming 
black,  CuO,  on  boiling. 

CuS04  +  2NaOH  =  Cu(OH)2  +  Na2S04 

Copper  Hydroxid. 

and 

Cu(OH)2+heat=CuO+H20. 

26.  Ferrocyanid     Test.— K4Fe(CN)6=a     brown     ppt.     of 
Cu2Fe(CN)6,  insoluble  in  dilute  acids: 

2CuS04  +  K4Fe  (CN)  6 = Cu2Fe  (CN)  6 + 2K2S04. 

Copper  Ferrocyanid. 

27.  Chromate  Test. — K2Cr04  =  a  reddish-brown  ppt.  of  CuCr04, 
soluble  in  NH4OH  to  a  green  solution. 

CuS04 + K2Cr04 = CuCr04  +  K2S04. 

Copper  Chromate. 

40.  Cadmium. 

(Make  tests  on  a  solution  of  Cadmium  Chlorid.) 

28.  Precipitated  from  acid    solution  by  H2S= yellow  ppt. 
CdS  insoluble  in  (NH4)2S  but  soluble  in  HN03.     This  ppt.  will 
form  in  the  presence  of  potassium  cyanid  (distinction  from  copper) : 

CdCl2+H2S  =  CdS+2HCl. 

Cadmium 
Sulfid. 

29.  Ammonia   Test.— NH4OH  =  a  white  ppt.   of  Cd(OH)2, 
soluble  in  excess: 

CdCl2  +  2NH4OH  =  Cd(OH)2  +  2NH4C1. 

Cadmium 
Hydroxid. 

30.  Sodium-hydroxid  Test.—N&OH  =  a  white  ppt.  of  Cd(OH)2, 
insoluble  in  excess : 

CdCl2  +  2NaOH  =  Cd  (OH)  2  +  2NaCl. 

31.  Apply  sodium-carbonate  test.    A  brown  coating  of  CdO; 
no  metallic  bead. 


34  QUALITATIVE  CHEMICAL  ANALYSIS. 

41.  Arsenic. 

(Make  tests  on  a  solution  of  Arsenic  Chlorid.) 

32.  Precipitated  from  acid  solutions  by  H2S  =  a  yellow  ppt. 
of  As2S3 : 

As205 + 5H2S = As2S3  +  5H20 + S2. 

Arsenous 
Sulfid. 

Upon  boiling  and    passing  an  excess  of  H2S  through  the 
solution,  As2S5  is  pptd. 

33.  Ammonio-Silver-nitrate  Test. — AgN03  in  NH4OH  solu- 
tion =  a  reddish-brown  ppt.  of  AgsAs04. 

H3As04 + 3AgN03 = Ag3As04 + 3HN03. 

This  is  the  differentiating  test  from  arsenosum,  which  com- 
pare. 

42.  Arsenous. 

(Make  tests  on  a  solution  of  Arsenous  Chlorid.) 

34.  Precipitated  from  acid  solutions  by  H2S  =  a  yellow  ppt. 
of  As2S3,  soluble  in  (NH4)2S,  and  reprecipitated  by  HC1: 

2As203  +  6H20  =  4H3As03 
and 

4H3As03  +  6H2S  =  2As2S3  +  12H20. 

Arsenous  Sulfid. 

35.  Copper-sulphate   Test. — In  neutral  solutions  CuS04=a 
pale-green  ppt.  of  CuHAs03  (Scheele's  green),  soluble  in  NH4OH: 

H3As03 + CuS04  +  2NH4OH  =  CuHAs03  +  (NH4)  2S04 + 2H20. 

Copper  Arsenite. 

36.  Ammonio-Silver-nitrate  Test. — AgN03  in  NH4OH  solu- 
tion =  yellow  ppt.  Ag3As03  (silver  arsenite): 

H-jAsOs  +  3AgN03 = Ag3As03  +  3HN03. 

37.  Charcoal  Test. — Heated  on  charcoal,  arsenic  gives  a  white 
incrustation  and  a  garlicky  odor. 


INORGANIC  BASES  AND  ACIDS.  35 

38.  Apply  both  Marsh's  and  Fleitmann's  tests. 

Marsh's  Arsenic  Test. — Generate  hydrogen  with  dilute 
H2S04  and  metallic  zinc  in  a  bottle  furnished  with  a  jet  and 
funnel- tube.  After  the  gas  has  been  given  off  in  sufficient 
qu'antity  to  expel  all  the  air  contained  in  the  bottle,  the  gas 
is  ignited. 

In  order  to  minimize  the  danger  of  explosion,  it  is  advisable, 
before  igniting  the  gas,  to  place  an  empty  test-tube  over  the 
mouth  of  the  jet,  and  when  the  gas  has  been  given  off  for  about 
five  minutes,  ignite  the  gas  in  the  test-tube,  and  use  this  to  ignite 
the  gas  issuing  from  the  jet.  Notice  that  the  flame  is  yellow, 
due  to  the  sodium  in  the  glass.  Now  introduce  the  arsenical 
solution  through  the  funnel  tube,  a  little  at  a  time. 

The  yellow  flame  is  at  once  changed  to  a  bluish  flame  char- 
acteristic of  arsenic,  and  which  emits  a  garlicky  odor.  If  a 
piece  of  cold  porcelain  is  held  in  this  flame,  a  brownish-black 
spot  of  metallic  arsenic  is  deposited  upon  it.  (This  is  called  an 
arsenic-spot.)  The  zinc  and  sulfuric  acid  used  for  generating 
the  hydrogen  must  both  be  free  from  arsenic. 

Marsh's  test  is  based  on  the  formation  of  arsine  gas,  AsH3, 
the  product  of  the  action  of  nascent  hydrogen  upon  arsenic 
in  an  acid  medium: 

6Zn + 6H2S04 + As203  =  2AsH3  +  6ZnS04 + 3H20. 

Marsh's  test,  further,  is  used  to  differentiate  between  arsenic 
and  antimony  in  a  solution;  for  instance,  antimony  produces 
the  same  kind  of  spot  as  arsenic,  but  the  arsenic  spots  dissolve 
readily  when  treated  with  a  few  drops  of  a  hypochlorite  or 
euchlorin  solution,  while  the  antimony  spots  are  not  affected. 

39.  Fkitmann's  Test  for  Arsenic. — Place  a  fragment  of  metallic 
zinc  or  aluminum  in  a  test-tube  with  some  KOH  solution  and 
add  a  small  quantity  of  the  arsenical  solution. 

Heat  the  mixture  and  place  over  the  mouth  of  the  tube  a 
cap  of  poper  moistened  with  a  solution  of  AgN03.  The  arsine 
which  is  evolved  acts  uDon  the  silver  nitrate,  reducing  it  to 


36 


QUALITATIVE  CHEMICAL  ANALYSIS. 


metallic  silver,  which  is  shown  by  the  development  of  a  dark 
stain  on  the  paper. 

The  advantage  of  this  test  lies  in  the  fact  that  stibine,  SbH3, 
is  not  evolved,  as  is  the  caso  in  Marsh's  test,  and  hence  only 
arsenic  reacts  in  the  manner  described : 

Zn+2KOH  =  K2Zn02+H2; 

Potassium 
Zincate. 

H3  As03  +  3H2  =  Asli3  +  3H20 ; 

Arsine. 

AsH3  +6AgN03  -f  3H20  =  3Ag2  +H3AsO3  +6HN03. 

Metallic 
Silver. 

40.  U.  S.  P.  Arsenic  Test.— The  U.  S.  P.  and  N.  F.fix  a  permis- 
sible limit  of  arsenic  in  chemicals  and  employ  a  modification  of 
Gutzeit's  test  measuring  the  stain  produced  on  mercuric  bromid 
paper  and  comparing  this  with  a  standard  stain  prepared  under 
exact  conditions  of  the  test.     (See  U.  S.  P.  IX,  page  584.) 

41.  In  testing  bismuth  and  antimony  stilts  for  arsenic,  apply 
Bettendorf  s  test  for  arsenic.     (See  U.  S.  T.  IX,  page  586.) 

42.  Reinch's  Test  for  Arsenic  and  Antimony. — Acidify  a  por- 
tion of  ths  original  solution  with  HC1   and  introduce  a  strip  of 
bright  shiny  copper  foil  and  boL  for  a  few  minutes. 


Arsenic. 


Antimony. 


A  gray  film  is  deposited  on  the  coppe:1 
foil.  Wash  the  foil  in  water,  and  dn 
it  between  filter  papers.  Heat  in  a 
long,  perfectly  dry,  test-tube.  A 
wide  band  of  crystals  of  ^4s203  if 
deposited  on  the  cooler  portion  of 
the  tube.  These  crystals,  when 
viewed  by  a  hand  lens,  or  under  the 
microscope,  are  found  to  be  eight- 
sided.  They  are  soluble  in  water 
(distinction  from  Sb),  and  when  H2Q 
is  passed  into  the  acidulated  solu- 
tion, a  yellow  precipitate  results. 


A  black  film  is  deposited  on  the  copper. 
Wash  the  foil  in  water,  and  dry  it 
between  filter  papers.  Heat  in  a 
long,  perfectly  dry,  test-tube.  A 
band  of  amorphous  Sbz03  is  de- 
posited on  the  tube  near  the  copper. 
This  deposit  is  insoluble  in  water, 
but  soluble  in  a  solution  of  Potassium 
Bitartrate,  and  if  this  pcluiion  is 
treated  with  P2^  g?s,  it  gives  an 
orange  precipitate,  characteristic  of 
Sb. 


INORGANIC  BASES  AND  ACIDS.  37 

43.  Antimony. 

(Make  tests  on  a  solution  of  Antimony  Chlorid.) 

43.  Precipitated  from  acid  solutions  by  H2S  =  an  orange  ppt.  of 
80283,  soluble  in  (NH4)2S,  and  reprecipitated  by  HC1.     The  ppt. 
is  not  soluble  in  (NH4)2C03  solution  (distinction  from  arsenic) : 

2SbCl3  +3H2S =Sb2S3  +6HC1. 

Antimonic 
Sulfid. 

44  Copper  Test. — Metallic  copper  in  acid  solutions  of  anti- 
mony receives  a  grayish  deposit  of  antimony;  when  this  is 
heated  in  a  test-tube  a  white  ring  of  Sb203  forms  in  the  tube, 
near  the  copper : 

Cu5  +Sb4  +302  =  Cu5 +2Sb203. 

Metallic 
Copper. 

45.  Water  Test. — Slightly  acid  solutions  of  SbCl3  poured  in 
water = a  white  ppt.  of  (SbOCl)2  +  Sb203,  soluble  in  tartaric  acid: 

4SbCl3  +  5H20  =  (SbOCl)  2 +Sb203  +  10HC1. 

Powder  of  Algaroth. 

46.  Apply  Marsh's   Test.    Antimony  stain  is  insoluble  in 
hypochlorite  solution. 

44.  Stannic  Salts. 

(Make  tests  on  a  solution  of  Stannic  Chlorid.) 

47.  H2S  precipitates  from  acid  solutions  SnS2  =  a  yellow  ppt. 
slowly  soluble  in  (NH4)2S,  and  reprecipitated  by  HC1: 

SnCl4 + 2H2S  =  SnS2 + 4HC1. 

Stannic 
Sulfid. 


38  QUALITATIVE  CHEMICAL  ANALYSIS. 

48.  Sodium-hydroxid  7^.—  NaOH  =  white  ppt.  Sn(OH)4: 

SnCl4+4NaOH  =  Sn(OH)4+4NaCl. 

Stannic 
Hydroxid. 

49.  Molybdenum    Test.  —  (NH4)2Mo04=no    blue    coloration 
(distinction  from  stannous). 

45.  Stannous  Salts 

(Make  tests  on  a  solution  of  Stannous  Chlorid.) 

50.  Precipitated  by  H2S  from  acid  solution  as  SnS  =  a  brown 
ppt.  slowly  soluble  in  (NH4)2S;  reprecipitated  by  HCl  =  a  yellow 
ppt.  of  SnS2  : 

SnCl2+H2S  = 


51.  Sodium-hydroxid  Test.  —  NaOH  =  a  white  ppt.  of  Sn(OH)2; 
soluble  in  excess  of  reagent  : 

SnCl2  +  2NaOH  =  Sn(OH)2  +  2NaCl; 
Sn(OH)2  +  2NaOH  =  Na2Sn02  +  2H20. 

Sodium 

Stannite. 

52.  Mercuric  Test.  —  HgCl2  produces  in  solutions  of  stannous 
salts  a  white  ppt.  of  Hg2Cl2  which  darkens  on  boiling,  being 
reduced  to  Hg: 

SnCl2  +  HgCl2  =  SnCl4  +  Hg. 

53.  Molybdenum    Test.  —  (NH4)2Mo04=a    blue    ppt.     (dis- 
tinguished from  stannic.) 


INORGANIC  BASES  AND  ACIDS. 


39 


46.  CHART  FOR  THE  "COMPARATIVE"  OBSERVATION  OF  THE 
REACTIONS  OF  THE  METALS  OF  GROUP  II. 

DIVISION  A.    SULFIDS  INSOLUBLE  IN  (NH4)2S 


Reagents. 

Pb. 

Hg(ic). 

Bi. 

Cu. 

Cd. 

H2S    in 
pres- 

Black    ppt. 
PbS.  Solu- 

Reddish 
black    ppt. 

Brown  ppt. 

Bi2S3. 

Black   ppt. 
CuS.   Sol- 

Yellow ppt. 
CdS.  Solu- 

ence  of 

ble  in  hot, 

HgS.  Insol- 

Soluble  in 

uble   i  n 

b  1  e   in 

HC1. 

dilute 

b  1  e        in 

HN03. 

HNO3. 

HNO3. 

HNO3. 

HNO3. 

NaOH 

White     ppt. 
Pb(OH)2. 

Yellow  ppt. 
HgO.      In- 

White ppt. 
Bi(OH),. 

Blue     ppt. 
Cu(OH)2. 

White    ppt. 
Cd(OH)2. 

Soluble    in 

soluble     in 

Soluble  in 

Becomes 

Insoluble 

excess. 

excess. 

HNO3. 

black  on 

in  excess. 

boiling. 

NH4OH 

White     ppt. 
Insoluble  in 

White     ppt. 
HgNHaCl. 

White  ppt. 
Bi(OH)3. 

Blue    ppt. 
Cu(OH)2. 

White  ppt. 
Cd(OH)2. 

excess. 

Soluble    in 

Insoluble 

Soluble   in 

Soluble  in 

HC1. 

in  excess. 

excess  to  a 

excess. 

blue    solu- 

tion. 

KI 

Crystalline 
yellow  ppt. 

Red      ppt. 
HgI2.    Sol- 

Brown ppt. 
BiI3.    Sol- 

Dirty-white 
ppt.   CuI2 

Soluble    in 

uble  in  ex- 

uble in  ex- 

and free 

boiling 

cess  of  KI 

cess. 

iodine. 

water. 

and  HgCl2. 

K,CrO4. 

Yellow  ppt. 
PbCrO4. 

Reddish 
yellow  ppt. 
HgCr04. 

Yellow  ppt. 
Bi2O(CrO4)2 
Soluble  in 

Reddish- 
brown  ppt. 
CuCrO4. 

Yellow  ppt. 
CdCrO4. 
Soluble   in 

Soluble    in 

HNO3.  In- 

Soluble in 

acids. 

HNO3. 

soluble  in 

NH4OHto 

KOH. 

a  green 

solution. 

K4Fe- 
(CN).. 

White     ppt. 

Pb2Fe(CN)6. 

White     ppt. 
becomin  g 
blue     on 

Pale  yellow 
ppt.     Sol- 
uble   in 

Brown  ppt. 
Cu2Fe(CN)6. 
Insoluble 

Almost 
white  ppt. 
Cd2Fe(CN)«. 

long  stand- 

HC1. 

in  dilute 

Soluble   in 

ing. 

acids. 

HC1. 

40 


QUALITATIVE  CHEMICAL  ANALYSIS. 


46a.     CHART    FOR    THE    "COMPARATIVE"    OBSERVATION 
THE  REACTIONS  OF  THE  METALS  OF  GROUP  II 
DIVISION  B.     SULFIDS  SOLUBLE  IN  (NH4)2S 


OF 


Reagents. 

As. 

Sb. 

Sn. 

H2S    in 

presence 
of  HC1. 

ous. 

ic. 

Orange  ppt. 
Sb2S3.  Sol- 
uble   in 
HC1. 

ous. 

ic. 

Yellow  ppt. 
As2S3.  In- 
soluble in 
HC1. 

Yellow  ppt. 
As2S3.     In- 
soluble    in 
HC1. 

Brown  ppt. 
SnS.    Sol- 
uble   in 
boiling 
HC1. 

Yellow  ppt. 
SnS2.  Sol- 
uble in 
boiling 
HC1. 

NaOH 

White  ppt. 
Soluble  in 
excess. 

White  ppt. 
Sn(OH)2. 
Soluble  in 
excess. 

White  ppt. 
Sn(OH)2. 
Soluble  in 
excess. 

NH4OH 

White  ppt. 
Insoluble 
in  excess. 

White  ppt. 
Sn(OH)2. 
Darkens 
on  boiling 
in  excess. 

White  ppt. 
Sn(OH)4. 
Slightly 
soluble    in 
excess. 

NH4OH 
and 
AgN03. 

Yellow  ppt. 
Ag3AsO3. 

Brown    ppt. 
Ag3AsO4. 

NH4OH 
and 
CuSO4. 

Yellowish- 
green    ppt. 
CuHAsO3. 

Pale  green 
ppt. 
CuHAsO4. 

H2O 
acidu- 
lated. 

White  ppt. 
(SbOCl)2 
+Sb203. 

(NH4)2 
MoO4. 

Blue  color- 
ation. 

No  blue 
coloration. 

HgCl2. 

Marsh's 
Test. 

White  ppt. 
Hg2Cl2 
darkens 
on  boiling. 

Dark  stain  of  As  (metal- 
lic).    Soluble  in   NaCIO 
solution. 

Black  stain 
of  metallic 
Sb.  Insol- 
uble   in 
NaCIO. 

Fleit- 
mann's 
Test. 

Black  stain  of  Ag  (metal- 
lic) on  paper  moistened 
with  AgNO3. 

No  black 
stain      o  f 
Ag. 

CALIFORNIA    COL 
PHARMACY 


INORGANIC  BASES  AND  ACIDS. 


41 


47-     CHART  FOR  THE  IDENTIFICATION  OF  THE  METALS  OF 
GROUP  H  IN  A  SIMPLE  SALT 


Group. 

Reagent. 

Result. 

Indication 

Confirmatory  Tests  which  should 
be  Applied  to  Original  Solution. 

II 

If    no    ppt. 
with  HC1  or 
if    ppt.    is 

Black 
ppt. 

Pb 

Add  K2CrO4  =  Yellow  ppt. 
Apply  tests  under  paragraph 

28. 

an  excess  of 
the  reagent, 
pass  H2S 

Black 
ppt. 

X 

9 

Hg" 

Add  KI  =  red  ppt.  soluble  hi 
excess.  Apply  tests  under 
paragraph  37. 

the  acidi- 
fied .8  0  1  U  - 
tion. 

Dark 
brown 
ppt. 

£ 

..a 
^ 

Q 

Bi 

Add  KI  =  greenish-brown  ppt 
Apply  tests  under  para- 
graph 38. 

Black 
ppt. 

'3 

1 

— 

Cu 

Add   NH4OH=a  light  blue 
ppt.     Soluble  in  excess. 
Apply    tests    under    para- 
graph 39. 

Yellow 
ppt. 

Cd 

Add  NH4OH=a  white  ppt. 
Soluble  in  excess.  Apply 
tests  under  paragraph  40. 

Yellow    * 
ppt. 

^ 

As 

Ppt.  soluble  in  (NH4)2S,  re- 
precipitated  by  HC1.  Ap- 
ply tests  under  paragraphs 
41  and  42. 

Orange 
ppt. 

w 
fc 

•  a 

Sb 

Ppt.  soluble  in  (NH4)2S,  re- 
precipitated  by  HC1.  Apply 
tests  under  paragraph  43. 

Brown 
ppt. 

£ 
| 
~o 

02 

Sn 

Add  NaOH  =  white  ppt.; 
boil,  ppt.  is  insoluble.     Ap- 
ply tests  under  paragraph  44. 

Yellow 
ppt. 

Sn 

Add  NaOH  =  white  ppt.; 
boil,  ppt.  dissolves.     Apply 
tests  under  paragraph  45. 

42 


QUALITATIVE  CHEMICAL  ANALYSIS. 


48.      SYNOPSIS  OF  THE  SEPARATION  OF  THE   METALS 

OF  GROUP  II. 


To  the  fil- 
trate    o  f 
Group    I, 
or    to    a 
portion  of 
the  origi- 
nal   solu- 
tion acidi- 
ified  with 
HC1,  add 
H2S  gas 
in   excess 
=  ppt. 

Ppt.=   Pb    Hg    Bi    Cu    Cd     As    Sb    Sn 
+  (NH4)2S,  which  dissolves      As    Sb    Sn 

DIVISION  A 
Ppt.=   Pb    Hg    Bi    Cu     Cd 

DIVISION  B 

Solution  =                As    Sb 

Sn 

+HNO3,  which  eliminates  Hg 

+dil.  HCl+strong  HC1 
precipitates            As 

Solution  =  Pb     Bi     Cu     Cd 

Q/rlnfi/vn                                                        QK 

Sn 

+H,SO4  precipitates  Pb 

ooiution  —                       OD 

Boil,  add  Cu  turn- 
ings +HgCl2  precipitates 

Sn 

Solution  =              Bi    Cu    Cd 

+NH4OH    in    excess   precipi- 
tates                Bi 

Solution  =                         Sb 

Solution  =                      Cu     Cd 

• 

+HNO3  and  divide  into  two 
portions. 

Portion  1  -f  NH4OH  =blue 
solution  =            Cu 

Portion  2+NH4OH+HCl 

H-  H2S  gas  precipitates         Cd 

49.     CHART   FOR   SEPARATION   OF  GROUP  II. 

Pass  H2S  gas  into  the  warmed  filtrate  of  Group  I,  until  it 
smells  strongly  of  the  gas,  after  shaking.  Heat  to  boiling,  pass 
some  more  H2S  into  the  solution,  allow  the  precipitate  to  sub- 
side, and  filter.  Test  a  small  portion  of  the  filtrate,  diluted  with 
water,  by  passing  more  H2S  through  it,  to  see  if  the  precipita- 
tion is  complete.  Wash  the  precipitate  with  boiling  hot  water, 
until  free  from  acid,  collect  all  the  precipitate  on  a  filter  paper, 
and  reserve  the  filtrate  and  washings,  for  Group  III.  The  pre- 
cipitate may  contain  Cu,  Pb,  Hg,  Bi,  Cd,  As,  Sb,  Sn. 

Puncture  the  filter  paper,  and  completely  wash  the  precipitate 
into  a  clean  porcelain  crucible,  with  a  few  drops  of  NH4OH  and 
an  excess  of  (NH4)2S  and  filter. 


INORGANIC  BASES  AND  ACIDS. 


43 


DIVISION  A. 

Precipitate. 


10.  May  contain  Cu,  Pb,  Hg,  Bi,  Cd. 
over  the  ppt.,  and  filter. 


Wash,  pour  dilute  boiling  HNO3 


11.  Precipitate. 

Hg. 

Dissolve  in  aqua  regia  by  aid  of 
heat.  Evaporate  to  dry  ness,  di- 
lute with  H2O,  and  add  KI:  red 
ppt.  =  Hg. 


12.  Filtrate. 
Cu,  Pb,  Bi,  Cd. 
Add  dil.  H2SO4,  boil 
well  and  filter. 


13.  Precipitate. 

Pb. 

Dissolve  the  ppt.  in  NH4C2H3O2, 
made  by  adding  HC2H3O2  in  ex- 
cess to  NH4OH,  divide  into  two 
portions,  and  add  to 
P.  1,  KI=yellow  ppt.=Pb. 
P  2,  K2CrO4  =  orange  ppt.  =  Pb. 


14.  Filtrate. 
Cu,  Bi,  Cd. 
Dilute     with     H2O, 
add  excess  of  NH4OH, 
and  filter. 


15.  Precipitate. 

Bi. 

Puncture  filter  papar,  and  wash 
into  a  clean  test-tube,  with  a  small 
quantity  of  warm  dil.  HC1,  evap- 
orate to  a  low  bulk,  and  pour  into 
a  large  volume  of  cold  water: 
White  ppt.  =  Bi. 


16.  Filtrate. 

Cu,  Cd. 

A  blue  solution  in- 
dicates Cu.  Add  a 
little  HNO3.  Divide 
in  two  portions. 


Portion  1— Add  NH4OH:  blue 
=  Cu  or,  add  to  acidified  solution, 
someK4Fe(CN)6:  brown  ppt.=Cu. 


DIVISION  B. 

Filtrate. 


7.  May  contain  As,  Sb,  Sn.     Add  dilute  HC1,  filter  and  w.  sh.     Diss  Ive 
the  ppt.  in  strong  HC1,  boil  gently,  and  filter. 


8.  Precipitate. 

As. 

Apply  Marsh's  test. 
A  metallic  stain  =  As. 


9.  Filtrate. 
Sb  and  Sn. 
Divide  into  two  portions. 


Portion  1. 

B  .ilwith  copper  turn- 
ings and  add  HgCl2: 
white  or  grayish  ppt. 
=Sn. 


Portion  2. 

Apply  Marsh's  test.    If  a  metallic  stain 
ir* sol.  in  N..C1O  solution  is  produced :  =Sb. 


44  QUALITATIVE  CHEMICAL  ANALYSIS. 

50.  OBSERVATIONS  ON  GROUP  II. 

The  separation  of  the  members  of  this  group  requires  very 
careful  manipulation  to  insure  success. 

The  precipitate  may  contain  any  or  all  of  the  following 
metals  and  possess  characteristic  colors,  thus:  Black  or  brown- 
ish black:  CuS,  PbS,  HgS,  Bi2S3,  SnS.  Yellow:  CdS,  As2S3, 
As2S5,  SnS2.  Orange:  Sb2S3,  Sb2S5.  When  H2S  is  first 
passed  into  solutions  containing  lead  and  mercuric  mercury 
they  give  colored  precipitates  due  to  formation  of  double 
salts,  thus:  HgCl2Hg.  At  first  it  is  white,  then  it  turns  red, 
brown,  and  finally  black  under  the  continuous  action  of  H2S, 
owing  to  the  formation  of  HgS.  Lead  salts  under  like  condi- 
tions give  red  precipitates  gradually  changing  to  brown,  then 
to  black,  owing  the  conversion  to  PbS. 

In  addition  to  the  above-mentioned  sulfids  of  this  group 
a  white  precipitate  of  sulfur  is  formed,  especially  if  the  original 
solution  is  very  acid  or  when  it  contains  a  ferric  salt,  chromic 
or  nitric  acid,  or  a  chlorate.  These  substances  being  strong 
oxidizing  agents  will  be  reduced  by  the  H2S,  precipitating 
sulfur,  which  is  easily  distinguished  from  CdS  and  As2S3  by 
its  lighter  color  and  density. 

Ferric  salts  will  be  reduced  to  ferrous  salts: 

2FeCl3 +H2S  =  2FeCl2  +2HC1 +S. 
Chromic  acid  will  be  reduced  to  chromic  chlorid: 
2H2Cr04  +3H2S  +6HCl  =  Cr2Cl6  +S3  +8H20 
Nitric  acid  will  be  reduced  to  nitric  oxid: 
2HN03  +3H2S=2NO  +S3  +4H20. 

As  said  above,  it  is  almost  useless  to  pass  H2S  into  very 
acid  solutions,  especially  those  containing  HN03  or  aqua 
regia.  If  these  acids  have  been  used  in  dissolving  the  original, 
the  solution  so  formed  should  be  first  evaporated  to  dryness 


INORGANIC  BASES  AND  ACIDS.  45 

the  residue  dissolved  in  a  little  water  with  the  aid  of  a  few 
drops  of  HC1,  before  passing  H2S  into  it.  It  is,  however, 
essential  that  the  solution  be  slightly  acid;  this  is  necessary 
to  prevent  the  precipitation  of  Zn,  Co,  and  Ni. 

Complete  precipitation  of  the  second  group  often  seems 
tedious,  but  it  should  under  no  circumstances  be  scamped, 
if  accurate  and  definite  results  are  to  be  obtained. 

To  attain  this  end  it  is  necessary,  first,  to  use  a  sufficient 
quantity  of  H2S;  second,  to  test  a  portion  of  the  solution  by 
filtration,  dilution,  and  repeated  precipitation  until  the  satura- 
tion be  complete. 

The  metals  precipitate  much  more  quickly  from  a  hot  than  a 
cold  solution,  especially  arsenicum;  its  yellow  precipitate  forms 
very  slowly,  thus:  2H3As04+5H2S  =  As2S5+8H20;  and  to 
facilitate  its  precipitation  the  solution  should  be  well  heated 
from  time  to  time. 

Besides  the  above  reason,  the  sulfids  thus  precipitated  from 
hot,  weakly  acid  solutions  and  allowed  to  stand  may  be  filtered 
much  more  easily,  for  they  exhibit  to  a  marked  degree  the 
property  of  becoming  "  colloidal"  and  consequently  passing 
through  the  filter-paper  upon  washing.  If  water  saturated 
with  H2S  or  very  dilute  acetic  acid  be  used  for  washing  the 
precipitate,  this  tendency  is  checked. 

51.  NOTES  ON  GROUP  II. 

7.  The  object  of  adding  a  little  NH4OH  before  the  addi- 
tion of  (NH4)  2S  is  to  neutralize  the  acid  present,  thus  preventing 
the  precipitation  of  sulfur.  The  precipitate  should  be  digested, 
not  boiled:  boiling  precipitates  some  As,  Sb,  Sn.  These  sulfids 
unite  with  the  (NH4)2S,  with  the  formation  of  salts  of  the 
sulfo-acids,  thus: 

+  3(NH4)2Sx=2(NH4)3AsS3; 


SnS  +  (NH4)2S,=  (NH4)2SnS2. 


CALIFORNIA    COLLEGE 
°f    PHARMACY 


46  QUALITATIVE  CHEMICAL  ANALYSIS. 

The  (NH4)2S  solution  should  be  warmed  with  diluted  HC1  (the 
strong  acid  dissolves  Sb2S3).  This  reprecipitates  all  the  sulfids 
which  must  be  filtered  off  and  washed  from  the  soluble  ammonium 
compounds.  This  reprecipitation  is  due  to  the  instability  of 
the  free  acids  (formed  by  the  HC1)  corresponding  to  the  sulfo- 
acid  ammonium  compounds  above  mentioned.  On  adding 
strong  HC1  and  boiling,  Sb  and  Sn  dissolve  as  chlorids,  while 
the  yellow  arsenic  sulfid  remains  undissolved.  The  boiling  is 
necessary  to  drive  off  the  H2S. 

8.  The  black  spot  formed  in  Marsh's  test  is  soluble  in  solu- 
tions of  chlorinated  soda  or  calcium.     If  part  of  the  solution 
is  treated  with  CS2,  and  this  solution  allowed  to  evaporate 
spontaneously,  free  S  is  separated. 

9.  The  acid  solution  on  being  boiled  with  metallic  copper 
(preferably  turnings),  reduces  the  stannic  chlorid  to  stannous 
according  to  the  reaction  SnCU  +  Cu  =  SnCl2  +  CuCl2.     The 
SnCl2    reduces   mercuric    chlorid    (HgCl2)    to    the   mercurous 
chlorid  (Hg2Cl2)  or  gray  metallic  Hg,  according  to  the  quantity 
of  SnCl2  present. 

10.  The  precipitate  should  be  well  washed  to  insure  absence 
of  the  metals  of  Group  III,  as  the  (NH4)2S  will  precipitate  the 
metals  of  the  aluminum  and  iron  groups. 

11.  Mercuric    sulfid    (HgS)    is   insoluble   in   boiling   dilute 
HNOs,  but,  owing  to  the  presence  of  other  sulfids,  the  treat- 
ment with  HNOs  will  cause  evolution  of  H2S  and  formation  of 
nitrates  and  free  sulfur,  thus: 

3H2S  +2HN03  =  S3  +2NO  +4H20. 

The  free  sulfur  thus  formed  occludes  a  portion  of  the  sulfids 
other  than  HgS,  and  protects  them  from  action  of  the  HNOs. 
Therefore  the  black  residue  thus  formed  which  is  insoluble  in 
HN03  should  always  be  further  tested  before  rejecting  it. 

HgS  dissolved  in  aqua  regia  forms  HgCl2;  this  should  be 
evaporated  to  dryness  to  get  rid  of  the  chlorin,  which  would 
liberate  free  iodin  on  the  addition  of  KI. 


INORGANIC  BASES  AND  ACIDS.  47 

When  the  chlorin  has  all  been  driven  off;  add  a  few  drops  of 
water  to  dissolve  the  HgCl2,  transfer  to  a  test-tube,  and  allow 
1  drop  of  KI  T.S.  to  slowly  run  down  the  side  of  the  test- tube,  till 
both  solutions  meet:  A  red  precipitate  forming,  indicates  Hg. 
The  KI  T.S.  is  added  in  this  manner,  because  the  red  iodid  of 
mercury  which  is  formed  is  soluble  in  an  excess  of  both  KI  and 
HgCl2.  Hg  may  further  be  identified  by  adding  a  few  drops  of 
solution  stannous  chlorid  (SnCl2),  when  a  grayish- white  precip- 
itate will  form.  Or,  the  precipitated  HgS  may  be  fused  with 
potassium  cyanid  (KCN)  and  sodium  carbonate  (Na2C03)  in  a 
dry  tube,  when  Hg  will  sublime  a  little  above  the  fused  mass. 

12.  The  sulfids  of  Cu,  Pb,  Bi,  Cd,  dissolve  in  the  nitric  acid, 
forming  corresponding  nitrates.     Evaporate  this  nitrate  solu- 
tion to  about  one-fourth  the  original  bulk  and  add  sufficient 
dilute  H2S04  to  displace  the  nitric  acid  and  form  corresponding 
sulf ates.    Continue  evaporation  until  white  H2S04  fumes  appear. 
This  is  a  sign  that  all  the  HNOs  is  dissipated,  which  is  important 
for  the  reason  that  lead  nitrate  might  remain  in  solution  and 
interfere  in  the  detection  of  cadmium. 

Cool  the  solution  of  sulfates,  and  dilute  with  water.  The 
sulfates  of  bismuth,  copper,  and  cadmium  go  in  solution  and 
may  be  readily  filtered  off  from  the  insoluble  PbS04. 

13.  Lead  sulf  ate  dissolves  readily  in  ammonium   acetate, 
forming  a  double  salt.    Divide  this  solution  into  two  portions;  to 
one  add  KI;  lead  iodid  will  form :  PbS04  +2KI  =  PbI2  +K2S04. 
To  the  other  portion  add  K2Cr04;   lead  chromate  will  form 
according  to  the  reaction    PbS04+K2Cr04  =  PbCr04+K2S04. 
Lead  iodid  forms  a  yellow,  and  the  chromate  an  orange-colored, 
precipitate.     Either  of  the  reagents  may  be  applied  directly  to 
the  PbS04  on  the  filter. 

14.  The  nitrate  must  be  slightly  diluted  with  water  before 
addition  of  NH4OH.     The  Cu  and  Cd  dissolve  in  the  ammonium 
hydroxid  to  form  soluble  ammonium  compounds,  while  the  Bi 
is  precipitated  as  hydroxid,  Bi(OH)3. 

15.  Filter  off  the  Bi(OH)3  and  dissolve  it  on  the  filter  by 


48  QUALITATIVE  CHEMICAL  ANALYSIS. 

pouring  warm  dilute  HC1  over  the  precipitate,  returning  the 
filtrate  until  all  the  precipitate  has  passed  into  solution.  The 
solution  contains  BiCl3,  and  on  evaporating  it  to  a  small  bulk 
to  free  it  from  excess  of  the  HC1  and  pouring  it  into  a  large 
volume  of  water,  a  white,  cloudy  precipitate  of  bismuth  oxy_ 
chlorid  (BiOCl)  is  produced.  The  evaporation  to  a  small  bulk 
above  directed  is  for  the  purpose  of  increasing  the  delicacy  of 
t  le  test,  as  the  less  HC1  used  for  dissolving  the  Li(OH)3  the 
more  positive  does  this  reaction  become. 

16.  If  the  solution  be  of  a  blue  cclcr,  it  indicates  the  pres- 
ence of  copper,  the  color  being  due  to  the  formation  of  a  new 
compound,  ammonio-sulfate  of  copper.  Add  to  this  solution  a 
few  drops  of  HN03,  and  divide,  into  two  portions,  a  and  b. 
To  portion  a  add  NH4OH;  a  blue  color  =  copper.  To  portion  b 
add  NH4OH,  acidulate  with  HC1,  and  pass  H2S  through  the  solu- 
tion; a  yellow  precipitate  indicates  cadmium  sulfid,  CdS. 

SPECIAL  TESTS  FOR  METALS  OF  GROUP  III. 

(ALKALI  SULFID  GROUP.) 
To  be  applied  to  separate  portions  of  the  solution. 

52.  Ferric  Salts. 

(Make  tests  on  a  solution  of  Ferric  Chlorid.) 

54.  (NH^S  precipitates  from  alkaline  solutions  (FeS-J-S),  a 
black  ppt.;  the  FeS  is  soluble  in  HC1: 

2FeCl3  +  3  (NH4)  2S  =  2FeS  +  S  +  6NH4C1. 


55.  K4Fe(CN)Q  Test.— K4Fe(CN)6  gives  a  deep  blue  ppt.  of 
of  Fe7(CN)i8  or  Fe4(Fe(CN)6)3  insoluble  in  acids: 

4FeCl3  +  3K4Fe(CN)6= Fe4Fe(CN)6)3  +  12KC1. 

Ferric 
Ferrocyanid. 


INORGANIC  BASES  AND  ACIDS.  49 

56.  K3Fe(CN)Q  Test.— K3Fe(CN)6  gives  a  brown  solution: 

2FeCl3  +  2K3Fe(CN)6=  Fe2(Fe(CN)6)2  +  6KC1. 

57.  Hydroxid  Test.—  Both  NaOH  and  NH4OH= brown  ppt., 
insoluble  in  excess : 

FeCl3+3NH4OH  =  Fe(OH)3+3NH4CL 

Ferric 
Hydroxid. 

58.  Sulphocyanid  Test.—~KCNS  =  blood-red  coloration: 

FeCl3  +  3KS(CN)  =  Fe(GNS)3 + 3KC1. 

Ferric 
Sulphocyanid. 

53.  Ferrous  Salts. 

(Make  tests  on  a  solution  of  Ferrous  Sulfate.) 

59.  (NH4)2S  precipitates  from  alkaline  solutions  FeS  soluble 
in  HC1  and  quickly  oxidized  in  the  solution  to  FeS04: 

FeCl2  +  (NH4)2S=FeS  +  2NH4Cl. 

Ferrous 
Sulfid. 

60.  Ferrocyanid  Test. — K4Fe(CN)6= white   ppt.  (distinction 
from  ferric),  rapidly  becoming  blue: 

2FeCl2  +  2K4Fe(CN)6=  2FeK2Fe(CN)6+4KCl. 

61.  Ferricyanid  Tes£.— K3Fe(CN)6= deep-blue  ppt.  insoluble 
in  acids : 

3FeCl2  +  2K3Fe(CN)  6  =  Fe3Fe2  (CN)i2  +  6KC1. 

Ferrous 
Ferricyanid. 

62.  Sulfocyanid  Test. — No  red  coloration  (distinction  from 
ferric). 

63.  Ammonia  Test. — NH4OH= greenish  ppt.: 

FeCl2  +  2NH4OH  =  Fe(OH)2  +  2NH4C1. 

Ferrous 
Hydrate. 


50  QUALITATIVE  CHEMICAL  ANALYSIS. 

64.  Hydroxid  Testf.—  NaOH=  white  ppt.  rapidly  becoming 
green,  then  brown  : 

FeCl2+2NaOH=Fe(OH)2  +  2NaCl. 

Ferrous 
Hydrate. 

54.  Aluminum. 

(Make  tests  on  a  solution  of  Aluminum  Sulfate.) 

65.  (NH4)2S  precipitates  from  alkaline  solutions  A12(OH)6 
insoluble  in  excess: 


Aluminum 
Hydroxid. 

66.  Phosphate  Test.  —  Na2HP04+NH4OH  +  HC2H302=  a 
white  ppt.  of  A1P04  insoluble  in  hot  HC2H302,  but  soluble  in  HC1  : 

A12  (S04)  3  +  2H3P04  =  2A1P04  +  3H2S04. 

Aluminum 
Phosphate. 

67.  Hydroxid  Test.—  Both  NH4OH  and  NaOH  give  a  gelat- 
inous white  ppt.  soluble  in  excess,  with  the  former  only  slightly 
soluble: 

A12  (S04)3  4-  6NaOH  =  AJ,  (OH)  6  +  3Na2S04. 

Aluminum 
Hydroxid. 

68.  Cobalt  Test.—  Co(N03)2  added  to  a  portion,  heated  on 
charcoal  gives  an  infusible  blue  mass. 

55.  Chromium. 

(Make  tests  on  a  solution  of  Chromium  Sulfate.) 

69.  (NH4)2S  precipitates  from  alkaline  solutions  Cr2(OH)6=a 
green  ppt.  soluble  in  diluted  HC1: 

Cr2(S04)3+3(NH4)2S  +  6H20  =  Cr2(OH)6+3(NH4)2S04+3H2S. 

Chromium 
Hydroxid. 

70.  Sodium-hypochlorite    Test.  —  Chlorinated    soda    solution 
(NaClO  +  NaCl)  boiled  with  an  alkaline  chromium  salt  gives  a 
yellow  solution  of  sodium  chromate,  (Na2Cr04). 


INORGANIC  BASES  AND  ACIDS.  51 

71.  Sodium-hydroxid  Test. — NaOH  =  a  bluish-green  ppt.  of 
Cr2(OH)e  soluble  in  excess,  and  reprecipitated  on  boiling: 

Cr2(S04)3  +  6NaOH  =  Cr2(OH)6 +3Na2S04. 

Chromium 
Hydroxid. 

72.  Ammonia  Test.—NR^OU  =  reaction  similar  to  NaOH. 

73.  Borax-bead  Test.— The  bead  is  emerald-green  in  color. 

56.  Zinc. 

(Make  tests  on  a  solution  of  Zinc  Sulfate.) 

74.  Precipitated  in  presence  of  NH4C1  from  alkaline  solutions 
by  (NH4)2S  as  ZnS  =  a  white  ppt.  soluble  in  HC1: 

ZnS04  +  (NH4)2S  =  ZnS  +  (NH4)2S04. 

Zinc 
Sulfid. 

75.  Cobalt  Test. — Heat  a  portion  of  the  solution  on  char- 
coal with  a  drop  or  two  of  Co(N03)2  solution = a  green  mass 
which  is  infusible. 

76.  Ferrocyanid  Test. — K4Fe(CN)e  gives  a  white  gelatinous 
ppt.  of  Zn2Fe(CN)6  insoluble  in  diluted  acids: 

2ZnS04+K4Fe(CN)6  =  Zn2Fe(CN)6+2K2S04. 

77.  Ammonia  Test. — NH4OH  =  white  ppt.  soluble  in  excess: 

ZnS04  +  2NH4OH=Zn(OH)2+  (NH4)2S04. 

Zinc 
Hydrate. 

78.  Carbonate  Test.— NaC03  =  a  white  ppt.  soluble  in  NH4C1 
andinNH4OH: 

ZnS04 + Na2C03  =  ZnC03  +  Na2S04. 

57.  Manganese. 

(Make  tests  on  a  solution  of  Manganese  Sulfate.) 

79.  Precipitated  from  alkaline  solutions  by  (NH4)2S  as  MnS, 
a  flesh-colored  ppt.  soluble  in  diluted  HC1  or  HC2H302: 

MnS04 +  2(NH4)2S  =  MnS  +  2(NH4)2S04. 

Manganese 
Sulfid. 


52  QUALITATIVE  CHEMICAL    ANALYSIS. 

80.  Lead  Test. — Pb02  heated  with  some  of  the  substance  and 
HNOs  (until  free  from  nitrous  fumes)  and  poured  into  H20 
gives  a  purple  solution  of  permanganate: 

2MnS04 + 6HN03 + 5Pb02 

=  2HMn04 + 2PbS04 + 3Pb(N03)2  + 2H20. 

Permanganic 
Acid. 

81.  Alkaline-Hydroxid  Test.— NaOH  or  KOH  =  a  white  ppt.  of 
Mn(OH)2,  which  becomes  brown  upon  heating: 

MnS04 + 2NaOH = Mn(OH)  2 + Na2S04. 

Manganese 
Hydroxid. 

82.  Ammonia  TesZ.— NH4OH= white  ppt.  soluble  inNH4Cl: 

MnS04+2NH4OH  =  Mn(OH)2+  (NH4)2S04. 

Manganese 
Hydrate. 

83.  Carbonate  Test. — Na2C03  =  nearly  white  ppt.: 
MnS04 + Na2C03 + 02 = Na2Mn04 + Na2S04 + C02. 

84.  Carbonate  Test. — Heated  on  a  platinum  wire  with  some 
Na2C03  gives  a  green  mass. 

85.  Borax-bead  Test. — Bead  hi  0  flame  is  purple-colored. 

58.  Cobalt. 

(Make  tests  on  a  solution  of  Cobalt  Nitrate.) 

86.  In  alkaline  solutions  gives  a  black  ppt.  of  CoS  with 
(NH4)2S: 

Co(N03)2  +  (NH4)2S  =  CoS  +  2NH4N03. 

Cobllt 
Sulfid. 

87.  Ammonia  Test.— NH4OH=a  blue  ppt.  of  Co(OH)2  soluble 
in  excess  to  a  brown  solution,  and  reprecipitated  by  NaOH : 

Co(N03)2  +  2NH4OH  =  Co(OH)2  +  2NH4N03. 

Cobalt 
Hydroxid. 


INORGANIC  BASES  AND  ACIDS.  53 

88.  Borax-bead  Test  gives  a  blue  bead. 

89.  Cyanid  7^.— KCN  =  a  brown  ppt.  of  Co(CN)2  soluble  in 
excess  on  boiling  and  not   precipitated  by  chlorinated  soda 
solution  (distinction  from  nickel) : 

Co(N03)2  +  2KCN = Co(CN)2  +  2KN03, 
then 

Co(CN)2  +  2KCN=K(CN)2-fCo(CN)2. 

90.  Sodium  Hydroxid  Test.— NaOH  =  a  blue  ppt.  of  Co(OH)2, 
changed  to  red  on  boiling: 

Co(N03)2 + 2NaOH  =  Co(OH)2  +  2NaN03. 

Cobalt 
Hydrate. 

59.  Nickel. 

(Make  tests  on  a  solution  of  Nickel  Sulfate.) 

91.  Precipitated  from  alkaline  solutions  by  (NH^S  =a  black 
ppt.  of  NiS,  nearly  insoluble  in  dil.  HC1: 

NiS04  +  (NH4)2S  =  NiS  +  (NH4)2S04. 

Nickel 
Sulfid. 

92.  Sodium-Hydroxid  Test. — NaOH  =  a  green  ppt.  insoluble 
in  excess  not  changed  by  boiling : 

NiS04  +  2NaOH = Ni(OH)2  +  Na2S04. 

Nickel 
Hydroxid. 

93.  Ammonia  Test. — NH4OH  gives  a  precipitate  similar  to  92 
but  soluble  in  excess  of  the  reagent,  forming  a  violet-colored 
solution : 

NiS04+2NH4OH  =  Ni(OH)2  +  (NH4)2S04. 

94.  Cyanid  Test. — KCN  =  a  pale  green  ppt.  soluble  in  ex- 
cess.  When  boiled  with  chlorinated  soda  solution  =  a  black  ppt. : 

NiS04+2KCN  =  Ni(CN)2+K2S04. 

95.  Borax-bead  Test. — Purplish  brown:  hot;    pinkish  brown: 
cold. 


54 


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QUALITATIVE  CHEMICAL  ANALYSIS. 
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INORGANIC  BASES  AND  ACIDS. 


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QUALITATIVE  CHEMICAL  ANALYSIS. 


6l.     CHART  FOR  THE  IDENTIFICATION   OF  THE   METALS  OF 
GROUP  III  IN  A  SIMPLE  SALT. 


Group. 

Reagent. 

Result. 

Indication. 

Confirmatory  Tests  which  should  be 
Applied  to  Original  Solution. 

HI    , 

If    no    ppt. 
withH2S, 
add    to    a 
fresh     por- 
tion of  the 
original  so- 
tion,     first, 
NH4C1, 
then 
NH4OH, 
and 
(NH4)2S. 
Warm,  and 
filter. 

Black 
ppt. 

Fe(ic) 

Ppt.  soluble  in   HC1.     Add 

K4Fe(CN)e  =  heavy  blue  ppt.,  in- 
soluble in  acids.  Apply  tests 
under  paragraph  52. 

Black 
ppt. 

Fe(ous) 

Ppt.  soluble  in  HC1.  Add 
K4Fe(CN)6  =  white  ppt.  rapidly 
turning  blue.  Apply  tests  under 
paragraph  53. 

White 
ppt. 

Al* 

Ppt.  soluble  in  HC1.  Add  KOH 
=  white  ppt.,  soluble  in  excess, 
reprecipitated  by  NH4C1.  Apply 
tests  under  paragraph  54. 

Green 

ppt. 

Cr 

Ppt.  soluble  in  dil.  HC1.  Add 
KOH  =  green  ppt.,  soluble  in 
excess,  reprecipitated  by  boiling. 
Apply  tests  under  paragraph  55. 

White 
ppt. 

Zn* 

Ppt.  soluble  in  HC1.  Add 
K4Fe(CN)6  =  white  ppt.  Apply 
tests  under  paragraph  56. 

Flesh- 
colored 
ppt. 

Mn 

Ppt.  soluble  in  dil.  HC1.  Add 
KOH  =  white  ppt.;  shake;  turns 
brown.  Apply  tests  under  par- 
agraph 57. 

Black 
ppt. 

Co 

Ppt.  insoluble  in  dil.  HC1.  Add 
NH4OH  =  a  blue  ppt.  soluble 
in  excess  to  a  brown  solution. 
Apply  tests  under  paragraph  58. 

Black 

ppt. 

Ni 

Ppt.  almost  insoluble  in  dil.  HC1. 
Add  K3Fe  (CN)  6  =  yellow  ppt. 
Apply  tests  under  paragraph  59. 

*  If  the  ppt.  in  Group  III  is  white  in  color  and  does  not  answer  tests  for  Al  or  Zn,  it 
may  contain  insoluble  phosphates,  metals,  or  oxalates,  or  all  of  these.  Confirm  by  dissolving 
some  of  the  original  substance  in  cone.  HNOs  and  pouring  this  into  sol.  of  ammonium 
molybdate. 

Yellow  precipitate  or  coloration  on  boiling  indicates  insoluble  phosphate;  in  which  case 
treat  as  described  under  paragraph  86. 


INORGANIC  BASES  AND  ACIDS. 


57 


62.     CHART  FOR  A  "SHORT  METHOD"  OF  SEPARATING  METALS 
OF  GROUP  III  IN  A  SIMPLE  SALT. 


Fe  (ic). 

Fe  (ous). 

Al. 

Cr. 

NH4C1  + 
NH4OH 

Reddish  ppt. 

Greenish  ppt. 

White  ppt. 

Bluish-green 
ppt. 

+  (NH4)2S 

Turned  black. 

Turned  black. 

No.  further 
effect. 

No  further 
effect. 

Zn. 

Mn. 

Co. 

Ni. 

NH4C1  + 
NH4OH 

No  effect. 

No  effect. 

No  effect. 

No  effect. 

+  (NH4)2S 

White  ppt. 

Flesh-colored 
ppt. 

Black  ppt. 

Black  ppt. 

63.     SYNOPSIS  OF  THE  SEPARATION  OF  METALS  OF  GROUP  III. 

To  a  portion  of  the  original  solution  add  HNOs,  then  NH4C1  in  excess, 
then  NH4OH. 


DIVISION  A. 
Precipitate. 
Ppt.=                                Fe*  Al     Cr 

DIVISION  B 

Filtrate. 
Solution  =              Co    Ni    Zn     Mn 

+NaOH+H2O2  pre- 
cipitates                    Fe 

+cold  dilute  HC1 
precipitates         Co     Ni 

Solution  = 

Al    Cr 

Solution  =                              Zn    Mn 

Divide  solution  into  two  portions: 

Precipitate  = 

Co     Ni 

Solution  = 
Zn     Mn 

Portion  1 
AddHCl  =  NH4OH 

=  white  ppt.  =  Al 

Portion  2 
Add  HC2H3O2  + 
AgNO3=red 
ppt.  =Cr 

+aqua  regia  + 
KOH  precipitates 
Co. 

Boil,  cool  +NaOH 
dissolves  Zn 

Solution  =  Mn 

*  The  Fe  is  in  the  ferric  state,  having  been 
oxidized  by  the  HNOs.     To  determine  the 
original  state  of  the  iron,  place  a  portion  of 
the  original  solution  into  two  test  tubes.   To 
one,  add  KSCN:  a  red  coloration  indicates 
ferric  iron;   to  the  other,  add  KsFe(CN)6: 
a  dark  blue  color   or  ppt.  indicates  ferrous 
iron. 

Ppt  =  Ni 

58 


QUALITATIVE  CHEMICAL  ANALYSIS. 


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Here  also  account  mu 
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INORGANIC  BASES  AND  ACIDS.  59 

65.  OBSERVATIONS  ON  GROUP  III. 

18.  The  object  of  evaporating  the  filtrate  from  Group  II 
is  to  dissipate  the  H2S  and  thus   prevent  the  formation  of 
(NH4)2S,  which   in  turn  would   precipitate   the   iron,  cobalt, 
and  nickel,  etc. 

Attention  here  is  called  to  organic  substances  mentioned 
in  No.  18,  paragraph  64. 

The  precipitation  of  iron,  aluminum,  and  chromium  as 
hydroxids  can  only  be  accomplished  in  the  absence  of  organic 
acids  and  other  organic  substances,  like  sugar  or  glycerin,  con- 
taining several  of  the  hydroxyl  groups.  Therefore,  if  these  be 
detected  in  the  preliminary  tests,  evaporate  the  H2S  nitrate 
to  dryness,  heat  the  residue  with  a  few  drops  of  strong  HN03 
(thus  decomposing  organic  substances),  dissolve  the  residue 
in  HC1,  and  proceed  in  the  usual  way. 

19.  Should  organic  substances  be  absent,  boil  the  solution 
with  HNOs  to  oxidize  the  ferrous  salts  to  the  ferric  state  (thus 
insuring  the  complete  precipitation  of  iron  by  ammonia).    Excess 
of  HNOs  should  be  avoided. 

The  NH4OH  (which  should  be  added  until  the  solution 
smells  strongly  of  NH3)  precipitates  Fe(OH)3,  A1(OH)3,  and 
Cr(OH)s,  with  a  trace  of  manganese.  Zinc,  manganese,  cobalt, 
and  nickel,  which  are  also  precipitated,  form  soluble  hydroxids 
which  dissolve  in  the  excess  of  NH4OH,  and  are  found  in  the 
filtrate. 

Although  the  manganese  is  soluble  in  the  excess  of  NH4OH, 
during  the  heating  and  subsequent  filtration  employed  in  the 
separation  of  the  Al  and  Cr,  it  absorbs  oxygen,  and  from  man- 
ganous  becomes  oxidized  to  mangano-manganic  oxid  (Mi^Os), 
which,  being  insoluble  in  NH4OH,  is  precipitated  together 
with  the  Fe,  Al,  and  Cr.  The  object  of  adding  NH4C1  before 
the  group  reagent  NH4OH  is  to  prevent  the  precipita- 
tion of  Mg(OH)2-  It  forms  a  soluble  double  compound, 
MgCl2.2NH4Cl.  The  solution  of  NH4C1  also  facilitates  the 


60  QUALITATIVE  CHEMICAL  ANALYSIS. 

complete  solution  of  Co,  Ni,  Zn,  and  Mn  in  the  excess  of  NH4OH. 
To  completely  precipitate  the  Al  and  Cr,  the  mixture  must  be 
boiled. 

66.  NOTES  ON  GROUP  III. 

22.  Aluminate  of  potassium  (KA102)  is  colorless;   chromate 
of  potassium    (K2Cr04)    is   yellow;    manganate  of  potassium 
(K2Mn04)  is  green,  but  after  boiling  in  water  it  becomes  pink. 

23.  The  portion  of  the  solution  reserved  for  the  detection  of 
Cr  will  be  yellow  from  the  presence  of  K2Cr04,  indicating  Cr. 

The  object  of  acidifying  the  solution  with  acetic  acid  is  to 
convert  the  carbonates  into  acetates;  if  this  were  not  done, 
brown  argentic  oxid  and  white  plumbic  carbonate  would  be 
precipitated. 

24.  Neutralization  is  done  with  HC1,  which  at  the  same 
time  forms  aluminum  chlorid,  and  from  which  NH4OH  throws 
out  aluminum  hydroxid  as  a  gelatinous  precipitate,  A1(OH)3, 
insoluble  in  excess. 

25.  The  metals  are  precipitated  as  sulfids,  their  identity 
being  indicated  by  the  color  of  the  precipitate,  thus :  MnS,  flesh- 
colored;  ZnS,  white;  CoS  and  NiS,  black.    Excess  of  (NH4)2S 
should  be  carefully  avoided,  as  it  dissolves  some  of  the  NiS 
(in  which  case  the  filtrate  is  brownish  black).   A  black  filtrate 
is  evaporated  and  the  precipitate  in  the  form  of  black  NiS  is 
reclaimed.     Cold,  diluted  HC1,  should  be  used,  as  both  the  Ni 
and  Co  are  insoluble  in  it,  but  are  soluble  in  concentrated  HC1. 

26.  If  the  precipitate  is  not  black,  Co  and  Ni  need  not  be 
sought  for. 

31.  An  excess  of  HN03  and  of  Pb02  must  be  added,  in  order 
to  insure  complete  oxidation  to  the  permanganate  state. 

32.  When  dried  and  fused  the  hydroxids  lose  water  and 
are  converted  into  oxids,  Fe203,  A1203,  and  Cr203.     When 
treated  with  water  and  filtered,  the  Fe203  remains  as  an  insoluble 
reddish-brown   powder   on   the    filter.      The   A1203  combines 
with  the  alkaline  fusing  mixture  to  form  a  soluble  potassium 


INORGANIC   BASES  AND  ACIDS.  61 

aluminate  thus:  A1203+K2C03=2KA102+C02.  The  Cr203 
likewise  unites  with  the  fusing  mixture  in  the  presence  of  oxi- 
dizers,  according  to  the  following  reaction:  Cr203+03  =  2CrOs; 
then  2Cr03+2K2C03  =  2K2Cr204+2C02.  The  oxidizer  in  this 
case  is  KNOs;  KClOs  acts  similarly. 

When  the  ppt.  is  fused,  the  Mn  is  oxidized  to  green  potas- 
sium manganate  (K2Mn04);  this  being  soluble  in  the  water 
interferes  with  detection  of  the  Al  and  Cr.  This  green  solu- 
tion is  therefore  treated  with  alcohol,  drop  by  drop,  until  the 
green  color  is  discharged.  The  alcohol  is  reduced  to  aldehyd, 
which  in  turn  reduces  the  manganese  to  mangano -manganic 
oxid  (Mn203),  which  then  precipitates  and  should  be  filtered 
out  before  testing  for  Al  and  Cr. 

SPECIAL  TESTS  FOR  METALS  OF  GROUP  IV. 

(CARBONATE  GROUP.) 
To  be  applied  to  separate  portions  of  the  solution. 

67.  Barium. 

(Make  tests  on  Barium  Chlorid  solution.) 

96.  Precipitated  from  alkaline  solutions  (previously  heated) 
by  (NH4)2C03  =  BaC03;  soluble  in  acids  (except  H2S04): 

BaCl2  +  (NH4)2C03  +  2NH4C1 = BaC03  +4NH4C1. 

Barium 
Carbonate. 

97.  Sulfuric  Test.— H2S04=a  white    ppt.  BaS04  insoluble 
in  acids: 

BaCl2 + H2S04 = BaS04 + 2HC1. 

Barium 
Suifate. 

98.  Suifate  Test.—K2SO±  or  CaS04  =  a  white  ppt.  of  BaS04 
insoluble  in  acids: 

BaCl2  +  K2S04 = BaS04  +  2KC1. 

Barium 

Suifate. 


CALIFORNIA   COLLEGE 

of    PHARMACY 


62  QUALITATIVE  CHEMICAL  ANALYSIS. 

99.  Chromate    Test.— K2Cr04=a    yellow    ppt.    of    BaCr04 
insoluble  in  HC2H302 : 

BaCl2  +  K2Cr04 = BaCr04 + 2KC1. 

Barium 
Chromate. 

100.  Oxalate   Test.— (NH4)2C204=a  white  ppt.   soluble  in 
HC2H302 : 

BaCl2  +  (NH4)2C204 = BaC204 + 2NH4C1. 

Barium 
Oxalate. 

101.  Flame  Test. — Barium  salts  heated  with  HC1  on  a  plat- 
inum wire  =  a  green  flame. 


68.  Strontium. 

(Make  tests  on  a  solution  of  Strontium  Nitrate.) 

102.  Precipitated  from  hot  alkaline  solutions  by  (NH4)2COa 
=  a  white  ppt.  soluble  in  acids: 

Sr(N03)2  +  (NH4)2C03  =  SrC03  +  2NH4N03. 

Strontium 
Carbonate. 

103.  Chromate    Test. — K2Cr207  =  no    precipitate    except    in 
very  concentrated  solutions  when  it  becomes  yellow: 

Sr  (N03)2  +  K2Cr04  =  SrCr04 + 2KN03. 

Strontium 
Chromate. 

104.  Sulfate  Test.—  K2S04  or  CaS04=a  white  ppt.  of  SrS04 
(which  forms  very  slowly,  and  is  more  soluble  than  BaS04) : 


Sr(N03)2  +  CaS04  =  SrS04  +  Ca(N03)2. 

105.  Flame  Test. — Strontium  salts  heated  with  HC1  on  a 
platinum  wire  =  a  crimson-red  flame. 


INORGANIC  BASES  AND  ACIDS.  63 

69.  Calcium. 

(Make  tests  on  a  solution  of  Calcium  Chlorid.) 

106.  Precipitated  from  hot  alkaline  solutions  by  (NH4)2C03 
=  a  white  ppt.  of  CaCOs  soluble  in  acids: 

CaCl2  +  (NH4)2C03 = CaC03  +  2NH4C1. 

'  Calcium 
Carbonate. 

107.  Oxalate   Test.— (NH4)2C204  =  a  white  ppt.   of  CaC204 
nearly  insoluble  in  HC2H302 : 

CaCl2  +  (NH4)2C204  =  CaC204+ 2NH4C1. 

Calcium 
Oxalate. 

108.  Sulfate  Test. — K2S04  in  concentrated  solutions  =  a  white 
ppt.  of  CaS04: 

CaCl2+K2S04= CaS04+2KCl. 

Calcium 
Sulfate. 

109.  Flame  Test. — Calcium  salts  heated  on  a  platinum  wire 
with  HC1= orange-red  flame. 


COLL 


64 


QUALITATIVE  CHEMICAL  ANALYSIS. 


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INORGANIC  BASES  AND  ACIDS. 


65 


71-    CHART  FOR  THE  IDENTIFICATION  OF  THE    METALS  OF 
GROUP  IV  IN  A  SIMPLE  SALT. 


Group. 

Reagent. 

Result. 

Indication. 

Confirmatory  Tests  to  be  Applied  to 
Original  Solution. 

IV 

If  reagents 
of  Group 
III  give  no 
ppt.,  add 
(NH4)2CO3, 
warm  and 
filter. 

White 
ppt. 

Ba 

Ppt.   soluble  in   HC1.     Add 
K2CrO4  =  yellow    ppt.    Apply 
tests  under  paragraph  67. 

White 
ppt. 

Sr 

Ppt.     soluble     in     HNO3.    Add 
K2CrO4  =  no  ppt.     Add  solution 
of    CaSO4,    shake  =  white    ppt. 
Apply  tests  under  paragraph  68. 

White 
ppt. 

Ca 

Ppt.  soluble  in  acids.     Add 
K2CrO4  =  no    ppt.   x  Add     solu- 
tion    CaSO4,     shake  =  no     ppt. 
Add     (NH4)2C2O4  =  white     ppt. 
Apply  tests  under  paragraph  69. 

72. 


SYNOPSIS  OF  THE  SEPARATION  OF  GROUP  IV. 


To  a  portion  of  the  original  solution  (made  alkaline  with  NH4C1+NH4OH) 

add  (NH4)2CO3,  warm,  and  allow  to  settle. 


Precipitate 


Ba        Sr        Ca 


+HC2H3O2  dissolves 
Solution 


Ba        Sr        Ca 
Ba        Sr        Ca 


+K2CrO4  precipitates 


Ba 


Solution 


Sr        Ca 


+dilute  H2SO4  (1:50)  precipitates 


Sr 


Solution 


Ca 


66 


QUALITATIVE  CHEMICAL  ANALYSIS 


73- 


CHART  FOR  THE  SEPARATION  OF  GROUP  IV. 


33.  To  the  alkaline  filtrate  from  Group  III,  add  some  solution  (NH4)2Cp3, 
warm,  and  allow  to  rest  for  a  few  minutes;   if  a  ppt.  occurs,  it  may  contain 

Ba,  Sr,  Ca. 

Filter  and  reserve  the  filtrate  for  Group  V. 

34.  Collect    and   wash   the   precipitate,  and  reject  the  washings.     Add 
acetic  acid  and  then  add  some  solution  of  K2CrO4;  if  a  ppt.  occurs,  filter. 


35.  Precipitate  =  Ba. 

tYellow.  ppt. 
Dissolve  ppt.  in  HC1 
and  apply  flame  test. 
Green-colored       flame 
=  Ba. 


36.  Filtrate. 
May  contain  Sr,  Ca. 

Add  some  dilute  H2S04  (1:50),   shake  well, 
and  filter. 


37.  Precipitate. 

May  be  Sr. 
Moisten    ppt.    with 
HC1,  and  apply  flame 
test.    Crimson  flame  = 
Sr. 


38.  Filtrate. 
May  be  Ca. 

Neutralize  with  NH4OH, 
add  (NH4)2C2O4  =  white  ppt. 
=  Ca. 


74- 


OBSERVATIONS  ON  GROUP  IV. 


33.  The  metals  of  this  group  are  precipitated  as  carbonates, 
thus:  BaC03,  SrC03,  CaC03.  Magnesium  carbonate  is  not  pre- 
cipitated here  on  account  of  its  being  present  as  a  double 
magnesium-ammonium  soluble  compound  (MgCl2.2NH4Cl.) 

The  solution  with  the  precipitated  carbonates  should  only 
be  warmed,  not  boiled.  If  the  mixture  be  boiled,  the  precipi- 
tated carbonates  are  decomposed  into  chlorids  through  the 
presence  of  the  magnesium-ammonium  compound,  and  may  later 
be  mistaken  for  magnesium  when  Na2HP04  is  added  for  the 
detection  of  that  metal. 

The  above-mentioned  decomposition  into  chlorids  is  ex- 
plained by  the  following  two  reactions: 

(1)  CaCl2  +  (NH4)2C03  - CaC03  +2NH4C1. 

(2)  CaC03  +2NH4C1  =  CaCl2  +  (NH4)2C03. 


INORGANIC  BASES  AND  ACIDS.  67 

75.  NOTES  ON  GROUP  IV. 

34.  When  the  precipitated  carbonates  are  treated  with 
acetic  acid,  acetates  of  the  metals  are  formed  with  the  evolu- 
tion of  C02. 

When  neutral  potassium  chromate  is  added,  barium  is 
separated  as  yellow  barium  chromate  (BaCr04). 

36.  The  exact  separation  of  the  calcium  and  strontium  is 
tedious.    The  following  simple  method  based  on  the  solubilities 
in  water  of  SrS04  (1  in  7000)  and  CaS04  (1  in  400)  is  usually 
employed:   To  a  small  portion  of  the  filtrate  add  some  satu- 
rated solution  of  CaS04  and  set  the  mixture  aside  for  some 
time.    If  strontium  be  present,  SrS04  (a  white  ppt.)  will  be 
obtained.    To  another  portion  add  some  very  dilute  H2S04 
(1  in  50)  and  set  aside  for  complete  deposition  of  SrS04  (this 
will  contain  some  CaSO). 

37.  Apply  the  flame  test  for  the  strontium  (crimson  flame). 

38.  If  the  least  trace  of  calcium  be  present  in  the  filtrate, 
a  white  precipitate  of  calcium  oxalate  insoluble  hi  water  and 
acetic  acid  is  obtained  on  the  addition  of  ammonium  oxalate. 

SPECIAL  TESTS  FOR  METALS  OF  GROUP  V. 
To  be  applied  to  separate  portions  of  the  solution. 

76.  Magnesium. 

(Make  tests  on  a  solution  of  Magnesium  Sulfate.) 

110.  Precipitated  from  its  alkaline  ammonium-chlorid  solu- 
tion by  Na2HP04  as  MgNH4P04=a  white  ppt.,  from  concen- 
trated solutions,  and  a  crystalline  ppt.  from  dilute  solutions: 

MgS04 + NH4OH  +  Na2HP04 =MgNH4P04-f  Na2S04 + H20. 

Ammonio-magnesium 
Phosphate. 

111.  Alkaline-hydroxid  Test.— Both  NaOH  and  NH4OH=a 
white  ppt.  of  Mg(OH)2  soluble  in  NH4C1: 

MgS04 + 2NaOH = Mg(OH)2 + Na2S04. 


68  QUALITATIVE  CHEMICAL  ANALYSIS. 

112.  Charcoal  Test. — Heated  on  charcoal  with  a  drop  or  two 
of  Co(N03)2  solution,  leaves  a  pinkish  mass. 

113.  Carbonate  Test. — Sodium  carbonate  produces  a  white 
ppt.  of  basic  magnesium  carbonate,  soluble  in  NH4C1: 

4MgS04 + 4Na2C03  +  H20  =  Mg4(OH)2  (C03)  3  +4Na2S04 + C02. 

114.  Calcium  Hydrate  Test. — Ca(OH)2  =  a  white  ppt.  insol- 
uble in  excess.     Soluble  in  ammonium  salts : 

MgS04+Ca(OH)2  =  Mg(OH)2 


77.  Potassium. 

(Make  tests  on  a  solution  of  Potassium  Nitrate.) 

115.  Alkaline-tartrate  Test. — NaHC4H406=a  white  crystal- 
line ppt.  of  KHC4H4Oe  (in  concentrated  solutions  only).    This  is 
a  distinguishing  test  between  potassium  and  sodium,  the  latter 
not  giving  a  ppt.  with  alkaline  tartrate: 

KN03 + NaHC4H406 = KHC4H406+ NaN03. 

Potassium-hydrogen 
Tartrate.; 

116.  Platinum-chkrid  TesZ.— PtCl4=a  yellow  ppt.  of  K2PtCl6 
soluble  in  excess  of  water  (distinction  from  Na) : 

2KCl+PtCl=K2PtCl6. 


Double  Potassio- 
platinic   Chlorid. 

117.  Sodium-Cobaltic-nitrite  Test.— NaN02-Co(N02)2  in  pres- 
ence of  HC2H302  =  a  yellow  crystalline  ppt. 

118.  Flame  Test. — Potassium  salts  heated  with  HC1  on  a 
platinum  wire = a  violet   coloration  when  viewed   through  a 
blue  glass. 


INORGANIC  BASES  AND  ACIDS.  69 

78.  Sodium. 

(Make  tests  on  a  solution  of  Sodium  Chlorid.) 

119.  Alkaline-tartrate   Test.  —  NaHC4H406  =  no  precipitate 
(distinction  from  potassium) . 

120.  Platinum-chlond    Test. — PtCl4=no     precipitate    with 
sodium  salt  (distinction  from  potassium). 

121.  Antimony  Test. — K2Sb2Oe=a  white  crystalline  ppt.  of 
Na2Sb206  (metantimonate)  in  neutral  solutions  only  and  on 
vigorous  shaking: 

2NaCl + K2Sb206 = Na^baOe + 2KC1. 

122.  Flame  Test. — Sodium  salts  with  HC1  heated  on  platinum 
wire  give  intense  yellow  coloration  to  the  flame  (invisible  through 
blue  glass). 

79.  Lithium. 

(Make  tests  on  a  solution  of  Lithium  Chlorid.) 

123.  Phosphate  Test. — Na2HP04  in  boiling  solutions = a  white 
ppt.  of  Li3P04: 

3LiCl + Na2HP04  =  Li3P04 + 2NaCl + HC1. 

Lithium 
Phosphate. 

124.  Carbonate  Test. — Na2C03  in  concentrated  solutions = 
Li2C03: 

2LiCl + Na2C03  =  Li2C03  +  2NaCl. 

Lithium 
Carbonate. 

125.  Flame  Test. — Lithium  salts  heated  with  HC1  on  a  plati- 
num wire  =  a  bright-red  flame. 


70  QUALITATIVE  CHEMICAL  ANALYSIS. 

80.  Ammonium. 

(Make  tests  on  a  solution  of  Ammonium  Chlorid.) 
126.  Alkaline-tartrate  Tes£.—  NaHC4H406=  white  ppt.: 


NH4C1  +  NaHC4H406=  NH4HC4H406+  NaCl. 


Ammonium 
Acid  Tartrate. 


127.  Platinic-chlorid     Test.  —  PtCl4  =    a     yellow     ppt.     of 
(NH4)2PtCl6  (in  concentrated  solutions)  : 

2NH4Cl+PtCl4  =  (NH4)2PtCl6. 


Double  Ammonio- 
platininc  Chlorid. 


128.  Hydroxid  Test.—  Either  NaOH  or  Ca(OH)2  heated  with 
some  of  the  solution  gives  off  NH3  (detected  by  the  odor). 
This  vapor  turns  red  litmus  paper  blue  : 

NH4C1  +  KOH  =  NH3  +  KC1  +  H20. 


Hold  a  glass  rod  moistened  with  HC1  over  the  mouth  of  the 
test-tube:  white  fumes  of  NH4C1  are  formed: 

NH3+HC1=NH4C1. 


129.  Nessler's  Test.— Nessler's  reagent  (made  from  HgCl2 + KI 
till  ppt.  dissolves,  then  NaOH  in  excess)  gives  a  yellow  or  brown- 
ish ppt.  of  NHg2I  (di-mercuric  ammonium  iodid). 

NH3 + 2HgI2 + 3NaOH  =  NHg2I + 3NaI + 3H20. 


INORGANIC  BASES  AND  ACIDS. 


71 


8l.      CHART    FOR    THE    "COMPARATIVE"    OBSERVATION    OF 
REACTIONS  OF  METALS  OF  GROUP  V. 


NaOH. 

NH4OH. 

NasCOa. 

Na2HPO4. 

j  NaHC4H4O«. 

Mg 

White      ppt. 
Soluble    in 
NH4C1. 

White  ppt. 
Soluble  in 
NH4C1. 

White  ppt. 
Soluble  in 
NH4C1. 

White  ppt. 
in    concen- 
trated sols. 
Crystalline 
ppt.  in  dil. 
sols. 

K 

White  crys- 
talline ppt. 
in  concen- 
trated sol. 

Na 

No  white  crys- 
talline ppt. 

Li 

White     ppt. 
in    concen- 
centrated 
solutions. 

White  ppt. 
on  boiling. 

NH4 

NH3   gas 
given  off  on 
heating. 

NH3  gas 
given  off  on 
heating. 

White  ppt. 

PtCU. 

NaN02  • 
Co(NO2)2 

Sb. 

Ca(OH)2. 

Flame. 

Mg 

Heated     on 
charcoal 
with  cobalt- 
ic-nitrite 
solution  = 
pink  mass. 

White  ppt. 
Insoluble  in 
excess.  Sol- 
u  ble  in 
NH4C1. 

K 

Yellow  ppt. 
soluble  i  n 
excess  o  f 
water. 

Yellow  crys- 
talline ppt. 
in  presence 
ofHC2H3O2. 

Violet    color 
through 
blue  glass. 

Na 

No  ppt. 

White    crys- 
talline ppt. 
in  neutral 
sols,  on 
shaking. 

Yellow. 

Li 

Bright    red 
flame. 

NH4 

Yellow  ppt. 
in  concen- 
trated solu- 
tions. 

NESSLER'S  TEST. 
Brownish  or  yellow  ppt. 

72 


QUALITATIVE  CHEMICAL  ANALYSIS. 


82.    CHART  FOR  THE  IDENTIFICATION  OF  THE  METALS  OF 
GROUP  V  IN  A  SIMPLE  SALT. 


Group. 

Reagent. 

Result. 

Indication. 

Confirmatory  Tests  which  should  be 
Applied  to  Original  Solution.           ' 

V 

If  reagent  of 
Group  IV 
gives  n  o 
ppt.,  add 
Na2HPO4. 

White 
ppt. 

Mg 

Add  (NH4)2CO3  and  boil  =  white 
ppt'.  Apply  tests  under  par- 
agraph 76. 

KHC<H406 
(in  alcohol) 

White 
ppt. 

K 

Add  HC2H3O2  +  sodium-cobaltic- 
nitrite  =  yellow  ppt.  Apply  tests 
under  paragraph  77. 

Na2Sb2O6 

White 
crystal- 
1  i  n  e 
ppt.  on 
shaking 

Na 

Apply  flame  test  =  intense  yellow. 
Apply  tests  under  paragraph  78. 

Na2HPO4 

White 
ppt. 

Li 

Apply  flame  test  =  crimson  flame. 
Apply  tests  under  paragraph  79. 

KOH 

Odor  of 
NH3. 

NH4 

Add  Nessler's  reagent  =  brownish 
ppt.  Apply  tests  under  para- 
graph 80. 

83. 


SYNOPSIS  OF  SEPARATION  OF  GROUP  V. 


Divide  portion  of  the  original  solution  or  the  filtrate  from  Group  IV 
into  two  portions. 


PORTION  1 
Contains                              NH4    Li     Na 

K     Mg 

PORTION  2 
To  a  portion  of  original 
solution,   add   KOH   or 
NaOH  =  odor    of    NH3. 
Hold  a  glass  rod  moist- 
ened   with     HC1    near 
escaping     fumes  =  white 
clouds   of   NH4C1   indi- 
cate NH4. 

Add  NH4OH+Na2HPO4 
precipitates 

Mg 

Solution  contains                NH4        Li 

Na      K 

Evaporate  to  dryness,  1   Intense  yellow 

Na 

add  a  few  drops  of  1 
HCl,2milsH2Oand  [                NH< 
apply  flame  test.        J  Finally  red 

Li       K 
Li 

NH4 

K 

Add  sodium-cobaltic-nitrite 
precipitates 

K 

Solution  contains        NH4 

INORGANIC  BASES  AND  ACIDS.  73 

84.      CHART  FOR  THE  SEPARATION  OF  GROUP  V. 

39.  To  a  portion  of  the  original  solution  or  to  the  filtrate  from  Group 
IV,  add  NH4OH  and  Na2HPO4  and  filter. 


40.  Precipitate. 

May  be  Mg. 
Dissolve     in    HNO3 
and   add    excess    of 
Ca(OH)2:  a  white  ppt. 
-Mg. 


45.  The  original  so- 
lution must  be  tested 
forNH4.  AddKOH  + 
heat:  odor  of  NH3  = 
NH4. 


41.  Filtrate. 
May  contain 

Li,  Na,  K,  NH4. 
Evaporate    to    dry- 
ness,  add  a  few  drops 
of  HC1,  2  mils  of  water 
and  apply  flame  test. 


43.  Na. 
Flame  = 
intense  yel- 
low. 


44.  K. 

Add  sodium  cobaltic- 
nitrite  T.  S.  =  yellow 
ppt.  =K.  Apply  flame 
test:  violet  (through 
blue  glass)  =  K. 


85. 


OBSERVATIONS  AND  NOTES  ON  GROUP  V. 


The  filtrate  from  Group  IV  contains  only  the  salts  of  Mg,  K, 
Na,  Li,  and  NH4. 

39.  The   object   of  adding   NH4OH  before  the  Na2HP04 
is  to  render  the  ppt.  less  soluble  in  water. 

40.  If  magnesium  be  present,  it  is  indicated  by  a  crystalline 
precipitate  of  ammonio-magnesium  phosphate  (MgNEUPC^). 

This  precipitate  appears  only  on  standing.  Any  non- 
crystalline  precipitate  is  calcium  which  may  have  escaped 
from  the  previous  group. 

43.  The  platinum  wire  should  be  held  in  the  flame  for  a 
minute  or  two,  as  the  intense  yellow  flame  of  sodium  may 
obscure  the  red  of  the  lithium. 

44.  The  lithium  and  sodium  having  been  tested  for  by  the 


74  QUALITATIVE  CHEMICAL  ANALYSIS. 

flame  test,  and  as  they  do  not  react  with  sodium-cobaltic-nitrite, 
we  may  disregard  them  entirely  when  testing  for  K. 

45.  The  NH4  having  been  dissipated  by  evaporation,  it  must 
be  tested  for,  in  the  original  solution.  In  any  case,  NH4  must 
be  tested  for  in  a  portion  of  the  original  solution,  as  NH4OH  was 
added,  in  the  course  of  separations,  quite  frequently,  and  might 
be  detected  in  this  solution,  whereas,  the  original  solution  might 
not  contain  any  NH4. 


86.   CHART  FOR  THE  SEPARATION  OF  INSOLUBLE 
PHOSPHATES. 

46.  If  the  precipitate  in  Group  III  contains   phosphates, 
proved  by  ammonium  molybdate  test  (made  by  dissolving  some 
original  substance  in  strong  HNOs,  boil,  and  pour  into  a  solution 
of  ammonium  molybdate  and  boil.    Yellow  coloration  or  pre- 
cipitate indicates  insoluble  phosphates),  dissolve  the  precipitate 
in  a  very  small  quantity  of  HC1,  add  some  NaC2H302  and  then 
some  solution  FeCl3.    Boil  for  five  minutes  and  filter.     (The 
ppt.  contains  the  insoluble  phosphates  of  iron,  chromium,  and 
aluminum.) 

The  filtrate  is  tested  for  the  ordinary  metals  of  the  third  and 
fourth  groups  in  the  usual  manner. 

Fuse  the  ppt.  well  with  KNOs  and  Na2COs,  treat  with  boil- 
ing water  and  filter.  Test  a  portion  of  the  filtrate  f or  Cr  with 
a  solution  of  AgNOaf  a  red  ppt.  =  Cr.  The  remainder  of  the  fil- 
trate is  next  acidified  with  HC1,  and  an  excess  of  NH4OH  added; 
a  white  flocculent  ppt.=Al.  The  residue  on  the  filter  is  dis- 
solved with  a  few  drops  of  hot  aqua  regia,  diluted  with  water, 
and  added  to  some  KSCN  solution;  a  blood-red  coloration 
=  Fe. 

47.  If  the  original  substance  is  insoluble  and  was  found 
to  contain  phosphates,  employ  the  folio  whig  chart: 


INORGANIC  ACIDS  AND  BASES. 


75 


Boil  some  of  the  substance  with  a  very  small  quantity  of  HC1,  add  cold 
NaOH  in  excess,  filter.  The  residue  will  contain  the  iron  and  other  insoluble 
phosphates.  Digest  with  cold  acetic  acid  and  filter. 


Precipitate. 

FePO4. 
Reddish-white  ppt. 


Filtrate. 
Phosphates  of  Al,  Cr,  Co,  Ni,  Zn,  Mn,  Ba,  Sr, 

Ca,  Mg. 

Add  FeCls,  drop  by  drop,  until  a  pale-reddish 
tint  is  obtained.  Heat  for  some  time  and  filter 
while  hot. 


Filtrate. 

Members  of  Group  III  and  IV 
to  be  proved  in  the  ordinary 
way. 


NOTE. — The  important  insoluble  (in  water  and  acids)  substances  which 
iray  be  found  in  the  insoluble  residues  are:  C,  S,  BaSO4,  SrSO4,  CaSO4,  PbSO4, 
PbCl2,  AgCl,  CaF2,  silica  and  silicates,  and  native  oxids  of  Al,  Cr,  Fe,  and  Sn. 
Special  tests  should  be  applied  to  identify  these. 

87.  Borax  Bead  Test. — Borax,  Na2B407,  when  ignited  on  a 
loop  of  a  platinum  wire  forms  a  bead,  known  as  borax  bead, 
which  when  dipped  in  certain  compounds  or  their  solutions 
yields  a  colored  ghiss  useful  for  the  detection  of  many  of  the 
metallic  compounds,  thus: 


In  the  Oxidizing  Flame. 

In  the  Reducing  Flame. 

Indicates 

Hot. 

Cold. 

Hot. 

Cold. 

Green 
Blue 
Green 
Red 
Amethyst 
Purple-brown 

Blue 

Blue 
Green 
Bottle-green 
Colorless 
Reddish  brown 

Red 

Cu 
Co 
Cr 
Fe 
Mn 
Ni 

Yellowish 
Pink-brown 

Yellow 

88.     PREPARATION  OF  A  SOLUTION  FOR  ANALYSIS 
IN  THE  WET  WAY. 

The   molecules   of   reacting   substances   are   brought   into 
closer  contact  when  they  are  in  solution  than  otherwise,  and 


76  QUALITATIVE  CHEMICAL  ANALYSIS. 

hence  in  this  state  the  reaction  between  them  takes  place  more 
readily;  in  fact  most  substances  will  not  react  at  all  except 
in  the  presence  of  a  solvent  or  in  a  fused  state.  It  is  therefore 
important  to  bring  the  substance  (if  it  be  a  solid)  into  solution. 
For  analytical  purposes  all  substances  may  be  divided  into 
four  classes,  as  follows: 

1.  Substances  soluble  in  water. 

2.  Substances  insoluble  in  water  but  soluble  in  an  acid. 

3.  Substances  insoluble  in  an  acid  but  soluble  in  a  mixture 
of  acids. 

4.  Substances  decomposed  by  fusing  with  carbonates. 
Complex  substances  may  contain  compounds  belonging  to 

each  of  the  above  four  classes.  A  small  portion  is  heated 
with  some  water  in  a  test-tube  and  filtered;  the  filtrate  is  now 
tested  for  compounds  which  may  have  gone  into  solution. 
The  residue  is  next  treated  with  an  acid,  the  excess  of  the 
acid  evaporated  off,  the  substance  diluted"  with  water  and 
filtered,  and  the  filtrate  tested  for  substances  that  may  have 
been  dissolved,  etc.  The  order  most  frequently  followed  is: 
1st,  water ;  2d,  hydrochloric  acid,  dilute ;  3d,  HC1  concentrated ; 
4th,  nitric  acid,  dilute;  5th,  HN03  concentrated;  6th,  nitro- 
hydrochloric  acid;  7th,  sulfuric  acid. 

In  using  acids  as  solvents  care  must  be  taken  not  to  use  them 
in  excess;  if,  however,  an  excess  has  been  used,  evaporate  the 
solution  under  a  hood  to  drive  off  the  excess  of  acid.  If  the 
acid  is  the  proper  solvent,  very  little  of  it  will  dissolve  a  large 
quantity  of  the  substance. 

If,  after  going  through  the  above-mentioned  list  of  acid  sol- 
vents, the  substance  still  remains  insoluble,  it  may  consist  of 
BaS04,  PbS04,  C,  S,  oxids  of  tin,  silica  and  silicates,  fluorids; 
alumina  and  aluminates,  Sb203  and  Sb20s,  chrome  iron  ore, 
some  metaphosphates,  arsenates,  silver  chlorid,  etc.  Fuse  a 
small  portion  of  the  powder  with  about  five  times  its  bulk  of  a 
fusion  mixture  (Na2C03+KN03)  in  a  small  crucible  (preferably 
platinum),  extract  the  fused  mass  with  water,  and  filter.  Dis- 


* 


INORGANIC  BASES  AND  ACIDS.  77 

solve  what  remains  on  the  filter  in  HC1;  if  this  does  not  effect 
solution,  try  HN03. 

NOTE  1.  If  the  preliminary  examination  shows  absence  of 
Pb,  boil  the  powder  with  NaOH  solution,  thus  avoiding  the 
more  difficult  and  tedious  fusion. 

The  action  of  the  fusion  mixture  in  the  above  operation 
is,  generally  speaking,  to  convert  the  base  into  an  oxid  or  a 
carbonate,  the  acid  of  the  substance  combining  with  the  Na 
and  K  as  a  corresponding  salt. 

NOTE  2.  It  should  be  remembered  that  the  excess  of  any 
acid  solvents  must  be  removed  before  proceeding  to  examine  for 
metals  of  the  second  group;  strong  acids  (a)  decompose  H2S 
into  its  elements  and  (6)  prevent  the  precipitation  of  some  of 
the  metals. 

Above  all  it  should  be  borne  in  mind  that: 

(1)  If  the  substance  is  solid,  it  must  be  finely  powdered 
before  effecting  solution. 

(2)  That  each  solvent  should  be  tried  first  cold,  and  then, 
if  required,  hot. 

(3)  The   solution  for  analysis   should   be  neutral  or  just 
slightly   acid.     If   alkaline,   neutralize  with   HNOs,   any    pre- 
cipitate produced  being  filtered  off  and  examined  separately. 

(4)  Since  cyanids,  ferrocyanids,  cobalt  icyanids,  etc.,  greatly 
interfere  with  the   ordinary  processes  of  analysis,  it  is  best 
to  destroy  them  before   proceeding,  by  evaporating  some  of 
the  solution  to  dryness  with  H2S04,  whereby  all  the  metals 
will  be  obtained  as  sulfates. 

(5)  If  the  substance  is  a  hard  metal  or  alloy,  treat  it  as 
under  "  Alloys  and  Hard  Metals."     (Paragraph  89.) 

(6)  In  making  a  solution,  as  above  described,  by  the  use  of 
acids,  a  clue  to  the  identity  of  the  substance  is  frequently  obtained. 

(7)  Having   obtained   a  solution,   test  it  successively,   for 
metals  of  Groups  I,  II,  III,  IV  and  V,  or  by  the  table  under 
paragraph  93,  and  finally  for  the  acidulous  radical  as  described 
under  Acids  under  paragraph  94. 


78 


QUALITATIVE  CHEMICAL  ANALYSIS. 


89. 


ALLOYS  AND  HARD   METALS. 


Procedure. — Cut  the  alloy  into  very  small  pieces,  or  file  off  2  grams  of  it, 
or  hammer  it  out  flat  so  as  to  expose  the  largest  possible  surface  to  the 
action  of  the  acid.  Heat  about  2  grams  of  the  thus-prepared  substance  with 
about  40  c.c.  of  strong  HNO3  in  a  capsule,  evaporate  to  small  bulk  to  remove 
excess  of  acid,  dilute  with  H2O,  and  filter. 

i  :      i 


Precipitate. 

SnO2  and  Sb2p6  (as  hydroxids  or  as  arsenates). 
[Also  possibly  Bi  as  arsenate  or  phosphate,  and  Au 

and  Pt4.] 

Digest  with  zinc  and  dilute  HC1.  Test  the 
evolved  gases  for  arsine  by  the  AgNOs  test.  Resi- 
due on  the  zinc  may  consist  of  the  remaining 
metals.  Boil  for  some  time  with  strong  HC1  under 
hood,  and  filter. 


Filtrate. 

Apply  the  usual 
group  reagents  and 
identify  the  metals 
in  the  groups. 


Precipitate. 
Sb  [Bi,  Au,  Pt.] 
Digest    with    yellow 
(NH4)2S;     Sb    dissolves 
as  sulfo-salt.    Evaporate 
solution  to    d  r  y  n  e  s  s. 
Orange-red  residue  =  anti- 
mony. 


Filtrate. 
SnCl2. 

Add  HgCl2.  White 
ppt.,  turning  gray 
on  heating  =  tin. 


QO.  CHART  FOR  THE  "  COMPARATIVE "  OBSERVATION  OF  THE 
REACTIONS  OF  THE  METALS  WITH  THREE  COMMONLY 
USED  REAGENTS. 

GROUP  I. 


Reagent. 

NaOH. 

NH4OH. 

Na2C03. 

LEAD,  Pb 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Insol- 
soluble  in  excess. 

White  ppt.  (White 
lead.) 

SILVER,  Ag 

Brown  ppt.  Sol- 
uble in  NH4OH. 

Brown  ppt.  Sol- 
uble in  excess. 

White  ppt.  Soluble 
in  NH4OH. 

MERCURY 
(<nui)  Hg. 

Black  ppt.  Insol- 
uble in  NH4OH. 

Black  ppt.  Insol- 
uble in  excess. 

Yellow  ppt.  turn- 
ing black. 

GROUP  II. 


MERCURY  (ic) 
Hg. 

Yellow  ppt.  In- 
soluble in  excess. 

White  ppt.  Soluble 
in  HC1. 

Reddish-brown 
ppt. 

BISMUTH,  Bi 

White  ppt.  Soluble 
in  HNO3. 

White  ppt.  Insol- 
ble  in  excess. 

White  ppt. 

INORGANIC  BASES  AND  ACIDS. 


79 


CHART  FOR  THE  "COMPARATIVE"  OBSERVATION  OF  THE 
REACTIONS  OF  THE  METALS  WITH  THREE  COMMONLY 
USED  REAGENTS— (Continued). 

GROUP  II — (Continued). 


Reagent. 

NaOH. 

NEUOH. 

NaaCOs. 

COPPER,  Cu. 

Blue  ppt.  Becom- 
ing black  on  boil- 
ing. 

Blue  ppt.  Soluble 
in  excess,  to  a 
blue  solution. 

Bluish  ppt.     Black 
on  boiling. 

CADMIUM,  Cd 

White  ppt.  Insol- 
uble in  excess. 

White  ppt.  Soluble 
in  excess. 

White  ppt. 

ARSENIC  (cms) 
As. 

ARSENIC  (ic) 

As. 

ANTIMONY, 
Sb. 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Insol- 
uble in  excess. 

White  ppt.    Soluble 
in  excess. 

TIN,   (Stan- 
nous),  Sn. 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Dark- 
ens on  boiling  in 
excess. 

White  ppt.     Insol- 
uble in  excess. 

TIN    (Stan- 
nic), Sn. 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Slight- 
ly soluble  in  excess. 

White  ppt.     Insol- 
uble in  excess. 

GROUP  III. 


IRON  (Fer- 
rous), Fe. 

White  ppt.    Becom- 
ing    green,     then 
brown. 

Greenish  ppt. 

White  ppt.  Soluble 
in  excess.  Be- 
comes brown. 

IRON  (Fer- 
ric), Fe. 

Brown  ppt.  In- 
soluble in  excess. 

Reddish  ppt.  In- 
soluble in  excess. 

Reddish-brown  ppt. 

ALUMINUM, 
Al. 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Slight- 
ly soluble  in  excess 

White  ppt.  Slight- 
ly soluble  in  excess. 

CHROMIUM. 
Cr. 

Bluish-green  ppt. 
Soluble  in  ex- 
cess. 

Bluish-green  ppt. 
Soluble  in  excess. 

Green  ppt.  Slightly 
soluble  in  excess. 

COBALT,  Co. 

Blue  ppt.  Insol- 
u  b  1  e  in  excess. 
Changed  to  red  on 
boiling. 

Blue  ppt.  Soluble 
in  excess  to  a 
brown  solution. 

Pink  ppt.  Soluble 
in  NH4OH. 

NICKEL,  Ni. 

Green  ppt.  Insol- 
uble in  excess. 

Green  ppt.  Soluble 
in  excess  to  a  violet 
solution. 

Green  ppt.  Soluble 
in  NHiCl  and  in 
NH4OH. 

CALIFORNIA   COLLEGE 
of    PHARMACY 


80 


QUALITATIVE  CHEMICAL  ANALYSIS. 


CHART  FOR  THE  "COMPARATIVE"  OBSERVATION  OF  THE 
REACTIONS  OF  THE  METALS  WITH  THREE  COMMONLY 
USED  REAGENTS.— (Continued). 

GROUP  III — (Continued). 


,   Reagent. 

NaOH. 

NH4OH. 

Na2CO3. 

ZINC,  Zn. 

White  ppt.  Soluble 
in  excess. 

White  ppt.  Soluble 
in  NH4C1  and  in 
NH4OH. 

MANGANESE, 
Mn. 

White  ppt.  becomes 
brown  on  heating. 

White  ppt.  Soluble 
in  NH4C1. 

Nearly  white  ppt. 

GROUP  IV. 


BARIUM,  Ba. 

White  ppt.  in  con- 
centrated solution. 

White  ppt.  Soluble 
in  acids. 

STRONTIUM, 
Sr. 

White  ppt.  in  con- 
centrated solution. 

White  ppt.  soluble 
in  acids. 

CALCIUM,  Ca. 

White  ppt.  Spar- 
ingly soluble. 

WThite  ppt.  soluble 
in  acids. 

GROUP  V. 


MAGNESIUM, 
Mg. 

White  ppt.  Soluble 
in  acids.  Soluble 
in  NH4C1. 

White  ppt.   Soluble 
in  NH4C1. 

White  ppt.    Soluble 
in  NH4C1. 

POTASSIUM, 
K. 

SODIUM,  Na. 

LITHIUM,  Li. 

White  ppt.  in  con- 
centrated solution. 

AMMONIUM, 
NH4. 

Free  NH3  on  boiling. 

Free  NH3  on  boiling. 

INORGANIC   BASES  AND  ACIDS. 


81 


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QUALITATIVE  CHEMICAL  ANALYSIS. 


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INORGANIC  BASES  AND  ACIDS. 


83 


93.    CHART  FOR  THE  DETECTION  AND  SEPARATION  OF  A 
MIXTURE  OF  THE  METALS  OF  THE  FIVE  GROUPS. 


Add  HC1  in  excess  and  filter.  Reserve  filtrate  for  Group  II. 
Wash  the  ppt.  thoroughly,  reject  the  washings,  pour  boiling 
water  over  the  ppt.,  and  collect  the  filtrate. 


Precipitate  =  Ag  —  Hg  (ous)  . 
Pour  warmed  (not  hot)  NH4OH  over 
the  ppt.  and  collect  the  nitrate. 

1 

1 

Filtrate  =  Ag. 
Add    HN03  = 
white  ppt. 
Ag. 

Ppt.  =Hg(ows). 
Turns   black. 
Dissolve   in  aqua 
regia,     dil.     with 
H2O    and    add 
SnCl2  =  gray    ppt. 
Hg(ows). 

• 

Filtrate. 
Divide  in  two 
portions.  For.  1. 
add  K2CrO4  =  yel- 
low ppt.  Por.  2. 
Add  KI  =  yellow 

ppt'   pb. 


(Continued  on  page  84.) 


CALIFORNIA  COL 


84 


QUALITATIVE  CHEMICAL  ANALYSIS. 


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INORGANIC  BASES  AND  ACIDS. 


85 


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86 


QUALITATIVE  CHEMICAL  ANALYSIS. 


CHART  FOR  THE  DETECTION  AND  SEPARATION  OF    A  MIX- 
TURE OF  THE  METALS  OF  THE  FIVE  GROUPS— (Concluded). 


Filtrate  from  Group  III. 
Add  (NH4)2CO3,  warm  gently,  allow  to  rest  for  a  few  minutes,  then  filter. 
Reserve  filtrate  for  Group  V. 
Ppt.  Wash  thoroughly,  and  reject  the  washings. 
Puncture  the  filter  paper  and  wash  ppt.  into  a  test-tube,  add  HC2H3O2 
and  K2CrO4  and  filter. 

1 

1 

Ppt.  =  yellow  =  Ba. 
Dissolve    in    HC1 
and  apply  flame  test 
=  green  flame. 
Ba. 

Filtrate  =  Sr,  Ca. 
Add  dil.  H2SO4  (1:50),  shake  well,  and  filter. 

1 

1 

Ppt.  -Sr. 

Moisten   with    HC1 
and  apply  flame  test  = 
crimson  flame. 

Sr. 

Filtrate  =  Ca. 
Neutralize   with 
NH4OH,  add 

(NH4)2C204 
=  white  ppt. 

Filtrate  from  Group  IV. 
Add  NH4OH  and  Na2HPO4,  and  filter. 


Ppt.  =  Mg. 

Dissolve  in  HNO3, 

add    excess    of 

Ca(OH)2  =  white  ppt. 

Mg. 


Filtrate,  Li,  Na,  K,  NH4. 

Evaporate    to  dryness.     Add  a    few    drops    of 
HC1,  2  mils  of  water,  and  apply  flame  test. 


Solution  =  K,  NH4. 
Add    sodium    cobaltic-nitrite 
=  yellow  ppt. 


To  a  portion  of  original  solu- 
tion add  KOH  and  warm  =  an 
odor  of  ammonia. 
NH4. 


INORGANIC  BASES  AND  ACIDS.  87 

94.  THE  ACIDS. 

Acids  do  not  admit  of  being  separated  in  groups  and  the 
members  of  each  group  again  separated,  as  in  the  systematic 
examination  of  the  metals.  It  is  customary,  however,  to  group 
the  acids  hi  accordance  with  their  behavior  when  treated  with 
certain  reagents,  which  may  serve  to  indicate  the  presence  or 
absence  of  entire  groups  of  acids. 

Some  of  these  acids  will  give  reactions  with  the  reagent  of  two 
or  more  groups,  and  hence  may  be  found  listed  under  each  one  of 
these  groups,  but  in  the  text  the  acid  is  found  listed  under  the 
group  with  whose  group  reagent  the  acid  will  give  its  most 
important  or  best-known  reaction. 

GROUP  A.  THE  VOLATILE  ACID  OR  EFFERVESCING  GROUP. 

This  group  includes  acids  which  are  volatilized  or  decom- 
posed when  their  salts  are  acted  upon  by  a  dilute  mineral  acid. 

They  are:    Carbonic  (H2C03),  hydrosulfuric  (H2S),  nitrous 
(HN02),  sulfurous  (H2S03)  thiosulfuric  (H2S203),  hypochlorous 
(HC10),  and  hydrocyanic  (HCN). 
GROUP  B.  THE  BARIUM  GROUP. 

This  group  includes  acids  which  are  precipitated  by  BaCl2. 
Two  members  of  this  group  are  precipitated  by  BaCl2  in 
the  presence  of  HC1,  namely,  sulfuric  (H2S04)  and  hydro- 
fluorsilicic  (H2SiF6).    The  others  are  precipitated  by  the 
same   reagent  from   neutral   solutions   only.     They  are: 
Carbonic,   sulfurous,    thiosulfuric,   phosphoric    (H3P04), 
boric    (H3B03),    oxalic    (H2C204),    hydrofluoric    (HF), 
silicic  (H2Si02),  arsenic  (HsAsCh),  arsenous  (H-jAsOs), 
and  chromic  (H2Cr04). 
GROUP  C.  THE  SILVER  GROUP. 

This  group  includes  acids  which  are  precipitated  by  AgNOs 
from  solutions  acidulated  with  HN03,  but  which  are  not 
precipitated  by  BaCl2. 

They  are:  Hydrochloric  (HC1),  hydrobromic  (HBr),  hydriodic 
(HI),  hydrocyanic  (HCN),  hydrosulfuric,  sulfocyanic 


88  QUALITATIVE   CHEMICAL  ANALYSIS. 

(HCNS),    hydroferrocyanic    (H4Fe(CN)6),     and    hydro- 
ferricyanic  (H3Fe(CN)6). 
GROUP  D.  THE  OXIDIZING  GROUP. 

This  group  includes  acids  which  are  oxidizing  agents,  and 
liberate  oxygen  when  decomposed. 

They  are:  Nitric  (HN03),  nitrous,  chloric  (HC103),  acetic,  per- 
manganic (HMn04),  bromic,  iodic,  and  hypophosphoric. 
GROUP  E.  THE  ORGANIC  ACIDS. 

The  acids  of  this  group  with  the  exception  of  oxalic  and 
formic  char  on  heating. 

They  are  divided  into  three  divisions: 

Div.  I. — Ferric   chlorid:    acetic,   tannic,   gallic,   pyrogallic, 
phenol  (carbolic),  phenolsulphonic,  salicylic  and  benzoic. 
Div.  2. — CaC^:   tartaric  and  citric. 
Div.  3. — Acids  not  listed  under  other  groups. 

95.     SYSTEMATIC  ANALYSIS  FOR  THE  ACID. 

Before  proceeding  with  the  analysis  for  the  acids,  it  is 
important  to  ascertain  what  metals  are  present,  because  this 
will  aid  materially  in  the  rapid  detection  of  the  acid. 

A  knowledge  of  the  metal  present  enables  the  analyst  to 
avoid  making  needless  tests  for  acids  that  cannot  possibly  be 
present.  For  instance,  if  the  substance  under  analysis  is 
soluble  in  water,  and  lead  is  known  to  be  present,  it  will  be 
needless  to  look  for  acids  whose  lead  salts  are  insoluble,  namely, 
sulfuric,  carbonic,  hydrosulfuric,  oxalic,  chromic,  phosphoric, 
etc.  On  the  other  hand,  the  analysis  may  be  rapidly  and 
satisfactorily  completed  by  searching  for  such  acids  only  as 
will  form  soluble  salts  with  the  metal  present,  in  the  above 
case  acetic,  nitric,  etc.  Again,  if  the  original  substance  is 
soluble  in  water  and  barium  is  known  to  be  present,  it  will 
be  a  waste  of  time  and  energy  to  look  for  acids  of  Group  B. 
If  silver  is  present  in  a  soluble  salt  the  acids  included  in  Group 
C  cannot  possibly  be  present. 


INORGANIC  BASES  AND  ACIDS. 


89 


If  in  a  preliminary  examination,  the  substance  chars  on 
heating  to  redness,  organic  matter  is  present  and  organic  acids 
should  be  looked  for.  But  if  it  does  not  char,  it  will  be  unnec- 
essary to  enter  into  the  testing  for  organic  acids,  because  none 
can  possibly  be  present,  except  oxalic  or  formic. 

Thus  it  is  readily  seen  that  with  a  knowledge  of  the  metal 
contents  of  the  substance  under  examination,  the  identification 
of  the  acid  present  is  facilitated,  and  the  number  of  the  latter 
to  be  looked  for  is  comparatively  few. 


96.  GROUP  A.  VOLATILE  ACID  GROUP. 

STEP  I. — Preliminary  Examination  of  the  Dry  Substance.— 

Heat  in  a  test-tube  a  portion  of  the  dry  substance,  or  the  residue 
by  evaporation  with  three  times  its  bulk  of  strong  sulfuric 
acid  and  observe  effect. 


Result  observed. 


Colored  vapors  are  evolved. 
Violet  (coloring  starch  paste  blue) 

Reddish  (coloring  starch  paste  yellow) 

Greenish-yellow  (detonation  with 
odor  of  chlorin,  and  bleaching 
litmus). 

Yellow  (odor  of  chlorin). 

Brownish-yellow  (irritating). 

Colorless  gases  ensue. 
Odor  of  vinegar  (HC2H3O2). 
Odor  of  rotten  eggs  (H2S). 
Odor  of  burning  sulphur   (SO2) 

(bleaching  litmus). 
Odor  of  burnt  sugar  and  blackening. 
Odor  of  peach  kernels  (HCN). 
Odorless    gas    burning    with    a    blue 

flame  (CO). 
Odorless  gas  turning  lime  water  turbid 

(CO,). 
Odorless  gas  (oxygen). 

Gas   evolved   etches   glass,  test    best 

performed  in  a  lead  dish. 
Hydrochloric    acid    gas    is    evolved, 

forms  white  clouds  with  ammonia. 


Indication. 


/  lodate. 
I  lodid. 
/  Bromate. 
\  Bromid. 
Chlorate. 


Hypochlorite. 
f  Nitrite. 

\  Nitrate    (in    presence 
[      agents). 


of    reducing 


Acetate. 

Sulfid. 

Sulfite,   thiosulfate  or  reducing  agents 

acting  on  sulfuric  acid. 
Tartrate,  citrate  or  organic  matter, 
yanid. 
Oxalate,    ferro-   and   ferricyanid   and 

sulfocyanate. 
Carbonate,  oxalate  and  cyanate. 

Chromate,  dichromate  manganate, 

permanganate,  bromate  and  iodate. 
Fluorid  and  fluorsilicate. 

Jhlorid. 


9(J  QUALITATIVE  CHEMICAL  ANALYSIS. 

Caution.  When  strong  sulfuric  acid  is  added  to  certain 
compounds  such  as  chlorates,  iodates,  etc.,  an  explosion  is 
apt  to  occur,  hence  the  acid  should  be  applied  with  great  care, 
one  drop  should  be  first  added  and  the  effect  noted. 

If  step  I  gives  a  decided  indication  as  to  the  identity  of 
the  acid,  the  confirmatory  tests  should  be  applied.  If  the 
acid  is  not  found,  proceed  by  the  following  steps. 

The  tests  described  in  the  text  are  applied  to  salts  of  the  alkali 
metals  only,  for  in  such  combination  only  can  reliable  results  be 
obtained  in  all  cases. 

A  strong  acid  reaction  (blue  litmus  turning  red)  indicates 
that  the  acid  is  in  the  free  state. 

If  the  acid  is  not  combined  with  an  alkali  it  is  a  general 
rule  to  convert  the  salt  into  a  salt  of  sodium  by  boiling  with 
NaOH. 

The  ppt.,  if  any,  should  be  separated  by  filtration  and 
the  filtrate  tested. 

(a)  If  the  salt  is  soluble  in  water  and  neutral  or  alkaline 
in  reaction,  the  boiling  with  NaOH  is  generally  not  needed. 

(6)  If  the  substance  is  insoluble  in  water  but  soluble  in 
acids,  boil  a  portion  of  the  solid  with  a  strong  solution  of 
sodium  carbonate,  filter,  and  use  the  filtrate. 

(c)  If   the  substance  is  insoluble,   treat  as  described   for 
the  preparation  of  the  solution  for  analysis  of  insoluble  sub- 
stances, using  the  filtrate,  which  is  neutralized  with  NH4OH. 

(d)  In   those  cases  where  the  metal  present  is  one  whose 
hydroxid   is   soluble,    and   which   cannot   in   consequence   be 
removed   by  treatment  with  NaOH,  it  is  necessary  to  use, 
instead    of    the    latter,    Na2G03,    boil,   and   neutralize  with 
HN03. 


INORGANIC  BASES  AND  ACIDS.  91 

CHARACTERISTIC    TESTS    FOR    INDIVIDUAL    ACIDS. 

The  following  characteristic  tests  are  to  be  made  preferably 
upon  salts  of  the  acids  with  alkali  metals. 

CHARACTERISTIC  TESTS  FOR  THE  ACIDS  OF  GROUP  A. 
97.  CARBONIC  ACID,  CARBONATES  AND  BICARBONATES. 

Carbonic  Acid  (H2C03)  is  not  known  in  the  free  state,  as 
it  splits  up  into  CO 2  and  H20.  Carbonic  anhydrid  C02  is  a 
colorless,  odorless  gas  which, 'when  passed  into  a  solution  of 
Ca(OH)2  or  Ba(OH)2  produces  a  white  precipitate  of  CaCOs 
or  BaCOs  respectively.  When  brought  into  contact  with  blue 
litmus  paper,  it  turns  the  latter  wine-red,  but  the  blue  is  restored 
upon  heating,  the  C02  being  driven  off. 

Carbonate. — 1.  Treated  with  a  dilute  acid,  violent  effer- 
vescence takes  place,  carbonic  anhydrid  being  evolved,  which 
produces  turbidity  in  a  drop  of  Ba(OH)2  solution  held  on  a 
glass  rod  near  the  mouth  of  the  test-tube : 

Na2C03  +  2HC1  =  2NaCl + H20 + C02. 
C02  +  Ba(OH)2  =  BaC03  +  H20. 

2.  Treated  with  AgNOz  T.S.   gives  a  gray  ppt.  soluble  in 
acids. 

3.  Treated  with  HgCl2  T.S.  produces  a  reddish-brown  ppt. 

4.  Treated  with    a    cold    solution  of  Magnesium    Sulfate 
produces  a  white  ppt. 

Bicarbonates. — 5.  Treated  with  a  dilute  acid  behaves  like 
carbonate  (1). 

6.  Treated  with  HgCl2  T.S.  gives  a  white  ppt. 

7.  Treated  with  a  cold  solution  of  MgSO±  does  not  give  a 
white  ppt. 

98.          HYDROSULFURIC  ACID  AND  SULFIDS. 

8.  Hydrosulfuric  acid  (H2S)  (sulfuretted  hydrogen)  is  a  color- 
less gas  having  an  odor  of  rotten  eggs.    It  is  inflammable,  S02 
being  produced  by  its  combustion. 


92  QUALITATIVE  CHEMICAL  ANALYSIS. 

9.  Paper  moistened  with  lead  acetate  solution  is  blackened 
when  held  in  the  gas.     This  is  due  to  the  formation  of  PbS. 

10.  Sulfids. — Treated  with  dilute  hydrochloric  acid  evolve 
H2S,  which  may  be  recognized  by  the  tests  described  above. 
Usually  the  odor  of  H2S  is  a  sufficient  test. 

11.  Treated  with  AgN03  T.S.  =a  black  precipitate  of  Ag2S. 

12.  Treated    with   sodium-nitro-ferricyanid   in   an   alkaline 
solution  =  a  purplish-red  color. 

13..  Insoluble  sulfids,  upon  which  the  foregoing  tests  cannot 
be  applied,  should  be  fused  with  a  little  NaOH  on  a  porcelain 
crucible  cover;  if  the  fused  mass  is  placed  on  a  bright  silver 
coin  and  moistened  with  water,  a  black  stain  will  be  produced 
(Ag2S). 

99.  SULFUROUS  ACID  AND  SULFITES. 

Sulfurous  acid  (H2SOs)  may  be  looked  upon  as  a  solution 
of  S02  in  water.  It  is  recognized  by  its  odor  of  burning  sulfur. 

14.  Treated  with  BaCh  T.S.  in  slight  excess  gives  a  white  ppt. 
of  BaS04  due  to  the  inevitable  presence  of  sulfuric  acid.    This 
ppt.  is  removed  by  filtration  and  a  small  quantity  of  chlorin 
water  or  hydrogen  dioxid  added,  whereupon  a  copious  ppt.  of 
BaS04  is  formed.     This  is  due  to  the  oxidation  of  H2S03  to 
H2S04. 

15.  Treated    with     zinc     and    dilute    hydrochloric    acid    it 
evolves  H2S,  which  blackens  lead  acetate  paper : 

H2S03  +  3Zn  +  6HC1  =  3ZnCl2  +  H2S  +  3H20. 

16.  Sulfites. — Treated  with  #2$04  evolves  $02,  recognized' 
by  its  odor  of  burning  sulfur : 

Na2S03  +  H2S04 = Na2S04  +  S02  +  H20. 

17.  Treated  with  BaCl2  T.S.  or  CaCk  T.S.  gives  a  white  ppt. 
soluble  in  dilute  HC1. 

18.  Heated  with  a  small  piece  of  zinc  and  a  few  drops  of 
#2$04,  H2S  will  be  evolved,  which  blackens  lead  acetate  paper- 

19.  With  AgNOs  sulfites  produce  a  white  ppt.  which  on 
being  heated  darkens  and  deposits  metallic  silver. 


INORGANIC   BASES  AND  ACIDS.  93 

ioo.  THIOSULFATES. 

Thiosulfuric  acid  cannot  be  isolated  because  it  splits  up 
into  S02,  S,  and  H20.  The  chief  salt  of  this  acid  is  sodium 
thiosulfate  (Na2S203)  which  is  used  extensively  in  photog- 
raphy for  "  fixing  "  because  of  its  property  of  dissolving  the 
silver  halids. 

^0.  Dilute  HC1  added  to  a  solution  of  a  thiosulfate  produces 
a  slowly-forming  precipitate  of  sulfur  and  an  evolution  of 
S02: 

Na2S203  +2HCl  =  2NaCl +H20  +S02  +S. 

The  precipitation  of  sulfur  in  this  reaction  distinguishes 
thiosulfates  from  sulfites. 

21.  Silver    Nitrate    T.S.  added  in  slight  excess  produces  a 
white  precipitate  of  silver  thiosulfate;  this  precipitate  does  not 
form  if  the  thiosulfate  is  in  excess,  and  furthermore  redissolves 
if  an  excess  of  sodium  thiosulfate  is  added : 

2AgN03  +Na2S203 = Ag2S203  +2NaN03 
Ag2S203  +Na2S203  =  2NaAgS203. 

The  precipitate  of  silver  thiosulfate  is  very  unstable,  and 
decomposes  almost  as  soon,  as  it  is  formed,  becoming  yellow, 
brown,  and  lastly  black,  through  formation  of  Ag2S : 

Ag2S203  +  H20 = Ag2S + H2S04. 

22.  Ferric  Chlorid  T.S.  produces  a  reddish-violet  color  which 
gradually  disappears : 

2FeCl3  +  2Na2S203  =  2FeCl2  +  2NaCl  +  Na2S406. 

23.  Barium  Chlorid  T.S.  produces  a  white  precipitate.    Cal- 
cium chlorid  forms  no  precipitate  (distinction  from  sulfite) : 

BaCl2  +  Na2S203  =  BaS203  +  2NaCl. 


94  QUALITATIVE  CHEMICAL  ANALYSIS. 

ioi.        HYDROCYANIC  ACID  AND  CYANIDS. 

24.  CYANIDS.  —  Sulfuric  Acid  added  to  an  alkali  cyanid  gives 
odor  of  bitter  almonds  (HCN).* 

25.  Silver  Nitrate  T.S.  added  in  excess  to  hydrocyanic  acid 
or  a  cyanid  produces  a  curdy  white  precipitate  of  silver  cyanid, 
which  is  soluble  in  ammonia  water,  and  in  concentrated  hot 
nitric  acid,  but  not  in  dilute  nitric  acid.    It  is  also  soluble  in 
sodium  thiosulfate. 

26.  Scheele's  Iron  Test.  —  The  hydrocyanic  acid  or  the  cyanid 
is  made  strongly  alkaline  by  the  addition  of  potassium  hydroxid; 
to  this  is  added  a  little  ferrous  sulfate  and  ferric  chlorid,  the 
mixture  is  then  gently  heated  and  finally  acidified  with  hydro- 
chloric   acid.    A    precipitate   of   ferric    ferrocyanid    (Prussian 
Blue)  is  formed.    The  reactions  are  as  follows: 

(a)  HCN+KOH  =  KCN+H20. 

(6)  FeS04+2KOH  =  Fe(OH)2+K2S04. 

(c)  Fe(OH)2+KCN=Fe(CN)2  +  2KOH. 

(d)  Fe(CN)2+4KCN=K4Fe(CN)6. 

(e)  3K4Fe(CN)6+2Fe2Cl6  =  Fe4(Fe(CN)6)3+12KCl. 

27.  The  Sulfocyanate  Test.  —  To  the  cyanid  add  a  few  drops 
of  yellow  ammonium  sulfid  solution  and  evaporate  the  mixture 
to  dryness  at  a  gentle  heat.    The  residue,  which  consists  of 
ammonium  sulfocyanate,  is  treated  with  one  or  two  drops  of 
dilute  hydrochloric  acid  to  destroy  any  undecomposed  sulfid 
present.    A  drop  of  ferric  chlorid  solution  is  now  added  and  a 
blood-red  color  (Fe2(SCN)6)  is  produced. 

The  reactions  are  as  follows: 

(a)  2HCN  +  (NH4)2S  +  S2  =  2NH4SCN  +  H2S. 
(6)  6NH4SCN+2FeCl3  =  F 


*  (Caution:  The  gas  so  evolved  should  be  very  cautiously  sniffed,  it  being 
highly  poisonous.) 


INORGANIC  BASES  AND  ACIDS. 


95 


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CALIFORNIA   COLLEGE 

of   PHARMACY 


96 


QUALITATIVE  CHEMICAL  ANALYSIS. 


103. 


HYPOCHLORITES.     (R'CIO.) 


28.  Acetic  Acid  or  Dilute  Sulfuric  Acid,  added  to  a  solution 
of   a   hypochlorite,  causes  evolution  of  chlorin,  recognized  by 
its  odor  and  by  giving  a  blue  color  upon  trie  subsequent  addition 
of  potassium  iodid  and  starch  solution. 

29.  Indigo  or  Litmus  Solutions  treated  with  a  solution  of  a 
hypochlorite,  and  acidified  with  dilute  sulfuric  acid  are  decolor- 
ized. 


104. 


GROUP  B.    BARIUM  CHLORIC  GROUP. 


•    STEP  II. — To  a  portion  of  the  aqueous  solution  acidulated 
with  hydrochloric  acid,  add  a  little  barium  chlorid  T.S. 

A     ,  ..  .   ..  r    .    ..  f  sulfate,     or 

A  white  precipitate  indicates  I  «,        .7. 

[  Fluorsihcate. 

STEP  III. — To  another  portion  of  a  neutral  aqueous  solution 
add  barium  chlorid  T.S.,  and  observe  effect. 


Result. 


Indication. 


A   white  ppt.   sol.  in  acetic   and   all 
stronger  acids. 

A  white  ppt.  sol.  in  acids. 

A  white  ppt.  which  chars  when  heated 

on  platinum  foil. 
A      white     ppt.     which     effervesces 

violently  when  treated  with  dilute 

HC1. 
A  white  ppt.  which  when  treated  with 

dU.  HC1  evolves  SO2. 

A  white  ppt.  insol.  in  dil.  HC1. 

A  white  ppt.  sol.  in  excess  of  reagent, 

in  acids,  and  in  NH4C1. 
A  yellow  ppt.  sol.  in  HC1. 


f  Phosphate. 
V  Oxalate. 
/  Silicate. 
1  Fluorid. 
/  Tartrate. 
\  Citrate. 
Carbonate. 


/  Sulfite. 

1  Thiosulfate. 

I  Sulfate. 

1  Fluorsilicate. 

Borate. 

Chromate. 


INORGANIC  BASES  AND  ACIDS.  97 

CHARACTERISTIC  TESTS   FOR  ACIDS   OF   GROUP   B. 
105.         SULFURIC  ACID  AND  SULFATES. 

30.  SULFURIC  ACID  (H2S04)  a  heavy,  oily,  colorless  liquid. 
Upon  adding  water  to  the  acid  considerable  heat  is  produced. 

31.  Charring  Test. — A  piece  of  paper  or  wood  placed  in  strong 
sulfuric  acid  is  charred,  or  if  the  dilute  acid  is  evaporated  in 
contact  with  a  little  white  sugar  the  latter  is  charred.    This 
charring  is  due  to  the  abstraction  of  the  elements  of  water. 

32.  Precipitation   Tests. — Dilute  sulfuric   acid  gives  a  white 
precipitate  with  barium  and  lead  salts. 

33.  SULFATES. — Sulfates  are  soluble  in  water  with  the  excep- 
tion of  basic  sulfates  and  those  of  barium,  strontium,  and  lead. 
Silver  sulfate  and  calcium  sulfate  are  only  slightly  soluble. 

34.  Barium   Chlorid  Test. — BaCl2  added  to  a  solution  of  a 
sulfate  precipitates  white  BaS04  insoluble  in  dilute  acids  even 
on  boiling.    The  sulfate  solution  should  be  acidified  with  dilute 
hydrochloric  acid  before  the  barium  chlorid  is  added: 

K21S04  +  BaCl2  =  BaS04  +  2KC1. 

106.  HYDROFLUORSILICIC  ACID  (H2SiF6)  AND 

FLUORSILICATES. 

35.  FLUORSILICATES. —  Barium     Chlorid    gives    with    fluor- 
silicates  a  white  precipitate,  which  is  insoluble  in  hydrochloric 

acid: 

H2SiF6  +  BaCl2  =  BaSiF6  +  2HC1. 

36.  Potassium    Chlorid    gives    a   gelatinous    precipitate    of 
K2SiF6: 

H2SiF6  +  2KC1  =  K2SiF6  +  2H|C1. 

107.  PHOSPHORIC  ACID  AND  PHOSPHATES. 

37.  ORTHO-PHOSPHORIC   ACID    (H3P04).— This   is  a  strong 
acid  liquid,  which  when  heated  is  converted  into  pyro-  and 
finally  weta-phosphoric  acid,  which  remains  as  a  vitreous  residue. 


98  QUALITATIVE  CHEMICAL  ANALYSIS. 

38.  The  Magnesia   Test. — A  small  portion  of  the  acid  is 
supersaturated  with  ammonia  water,  and  some  magnesia  mix- 
ture added.    A  white  crystalline  precipitate  of  ammonio-mag- 
nesium  phosphate  is  formed  (NH4MgP04  +  6H20). 

39.  The   Silver   Nitrate  Test.— The  precipitate  obtained  in 
the  magnesia  test  is  washed  and  dissolved  in  dilute  acetic 
acid.    To  this  solution  some  silver  nitrate  T.S.  is  added  and 
a  yellow  precipitate  of  silver  phosphate  Ag3P04  results. 

40.  PHOSPHATES. — The    alkali   phosphates    are   soluble   in 
water;  most  of  the  other  phosphates  are  insoluble.    They  are, 
however,  soluble  in  dilute  acids  from  which  they  are  reprecip- 
itated  upon  neutralizing  with  an  alkali. 

41.  The  Barium  Test. — Barium  chlorid  gives  with  a  phos- 
phate a  white  precipitate,  which  is  soluble  in  acetic  acid  and 
in   all   stronger   acids.    The   white   precipitate   produced    by 
barium  chlorid  with  a  sulfate  is  insoluble  in  acids.    That  pro- 
duced with  an  oxalate  by  the  same  reagent  is  soluble  in  acetic 
acid  and  the  mineral  acids : 

Na2HP04 + BaCl2  =  BaHP04 + 2NaCl. 

42.  The  Silver  Test. — Silver  nitrate  gives  a  yellow  precip- 
itate of  silver  phosphate  which  is  soluble  both  in  nitric  acid 
and  ammonium  hydroxid : 

Na2HP04 + 3AgN03 = Ag3P04 + 2NaN03  +  HN03 . 

43.  The  Magnesia   Test. — Magnesia  mixture  gives  a  white 
crystalline  precipitate   (NH4MgP04  +  6H20)   soluble  in  dilute 
acids : 

Na2HP04 +MgCl2  +NH4OH  =  NH4MgP04 +2NaCl  +H20. 

44.  The      Molybdate       Test.  —  Ammonium       molybdate 
(NH4)2Mo04  dissolved  in  nitric  acid,  gives  with  phosphates  a 
canary-yellow    precipitate    of    ammonium    phosphomolybdate 
readily  soluble  in  alkalies.     (NH4)3P04,  12Mo03. 


INORGANIC  BASES  AND  ACIDS.  99 

108.  META-  AND  PYRO-PHOSPHORIC  ACIDS. 

45.  META-PHOSPHOKIC  ACID  (HP03).— A  glassy  solid,  con- 
verted by  boiling  water  into  ortho-phosphoric  acid. 

46.  Ammonio-silver    Nitrate    produces    a  white  precipitate 
(AgP03)  in  neutralized  solutions  only.    Soluble  in  nitric  acid 
and  in  ammonia  water,  also  soluble  in  an  excess  of  an  alkali 
meta-phosphate  (difference  from  pyro-phosphoric  acid  and  its 
salts). 

47.  Albumen  is  coagulated  (difference  from  pyro-phosphoric 
acid). 

48.  Magnesia  mixture  gives  no  precipitate  with  meta-phos- 
phates. 

49.  PYRO-PHOSPHORIC  ACID   (H4P207).— A  glass-like  solid, 
converted  by  boiling  water  into  ortho-phosphoric  acid. 

50.  Ammonio-silver  Nitrate. — Same  reaction  as  above  except 
that  the  precipitate  is  not  soluble  in  excess  of  alkali  pyro-  or 
meta-phosphate.    The  precipitate  is  Ag4P207. 

51 .  Albumen  is  not  coagulated. 

52.  Ammonium   Molybdate  gives  no  precipitate  with  pyro- 
phosphates  until  after  long  standing. 

109.  BORIC  ACID  AND  BORATES. 

BORIC  ACID  (HaBOs)  occurs  either  in  crystals  or  in  fine 
white  powder.  When  heated  to  100°  C.  orthoboric  acid  loses 
water  forming  meta-boric  acid  (HB02).  When  heated  to  160° 
C.  it  fuses  to  a  glassy  mass  of  tetra-boric  acid  (pyro-boric  acid) 
(H2B407). 

53.  Its  solution  in  alcohol  or  glycerine  burns  with  a  flame 
enveloped  with  a  green  mantle. 

54.  An  aqueous  solution  of  boric  acid  (1-50)  reddens  blue 
litmus,   and   turns   yellow   turmeric  paper  brownish-red  after 
drying  even  when  the  solution  has  been  acidulated  with  hydro- 
chloric acid.    This  brownish-red  color  is  changed  to  bluish- 
black  by  ammonia  water. 


100  QUALITATIVE  CHEMICAL  ANALYSIS. 

BORATES. — Sodium  tetra-borate  (Borax)  is  the  most  common 
and  hence  concerns  us  most.  Only  the  alkali  borates  are  soluble 
in  water. 

55.  Barium  Chlorid  produces  a  white  ppt.  soluble  in  acids. 

56.  The  Turmeric  Paper  Test.— A  piece  of  turmeric  paper  is 
moistened  with  a  solution  of  a  borate  slightly  acidified  with 
hydrochloric  and  the  paper  then  dried;    the  paper  becomes 
brownish-red  in  color.     If  the  paper  is  now  moistened  with 
ammonium  or  sodium  hydroxid  the  color  changes  to  bluish- 
black. 

57.  The  Flaine  Test. — If  a  drop  of  a  solution  of  borax  in 
glycerin  be  held  in  a  Bunsen  flame  a  transient  bright  green 
color  will  appear. 

58.  The  Gylcerin  Test. — An  aqueous  solution  of  borax  colors 
red  litmus  blue,  if  glycerin  be  added   to   this   solution,  boric 
acid  is  liberated  and  blue  litmus  is  turned  red. 

no.  OXALIC  ACID  AND  OXALATES. 

OXALIC  ACID  (H2C204)  colorless  crystals. 

59.  This  acid  added  to  an  acidulated  solution  of  potassium 
permanganate  completely  discharges  the  color  of  the  latter. 

60.  This  acid  added  to  a  solution  of  copper  sulfate  sets  free 
sulfuric  acid. 

61.  It  gives  all  the  reactions  of  oxalates. 

62.  OXALATES. — Concentrated  Sulfuric  Acid,  when  added  to 
an  oxalate  in  the  dry  state,  decomposes- it  with  the  evolution 
ofC02andCO: 

H2C204  +  H2S04  =  H20  +  H2S04  +  CO  +  C02. 
If  the  unmixed  gases  are  passed  through  lime  water,  the 
C02  will  be  absorbed,  forming  a  precipitate  of  CaCOs  and  the 
escaping  CO  may  be  ignited,  and  recognized  by  its  blue  flame. 

63.  Calcium    Chlorid   Test. — Calcium  chlorid  gives  a  white 
crystalline   precipitate   of   calcium   oxalate   soluble   in  hydro- 
chloric acid,  but  not  soluble  in  acetic  acid : 

K2C204 + CaCl2  =  CaC204 + 2KC1. 


»*    COLLtGt 
°t    PHARMACY 

INORGANIC  BASES  AND  ACIDS.  101 

64.  Barium    Chlorid    Test. — BaCl2  gives    a  white  ppt.   of 
barium  oxalate,  soluble  in  hydrochloric  acid  but  not  soluble  in 
acetic  acid. 

65.  The  Permanganate  Test. — Potassium  permanganate  solu- 
tion added  to  a  hot  solution  of  an  oxalate  acidulated  with  sulfuric 
acid  is  decolorized: 

5H2C204 + 3H2S04  +  2KMn04 

=  K2S04  +  2MnS04 + 8H20  +  10C02. 

in.    HYDROFLUORIC  ACID  AND  FLUORIDS. 

HYDROFLUORIC  ACID   (HF). — Very  corrosive.    It  acts  upon 
and  etches  glass. 

FLUORIDS. — (Practice  upon  fluor  spar  (CaF2).) 

66.  The  Etching  Test. — The  salt  is  powdered,  and  intro- 
duced into  a  platinum  or  leaded  dish  with  a  little  sulfuric 
acid.    The  dish  is  covered  with  a  piece  of  glass  previously 
coated  on  one  side  with  wax,  through  which  some  characters 
are  scratched  with  the  point  of  a  pin.    The  waxed  side  of  the 
glass  is  placed  over  the  dish  so  that  the  liberated  HF  comes 
in  contact  with  it,  and  the  dish  gently  heated,  being  careful, 
however,  not  to  melt  the  wax.    After  some  time  the  glass  is 
removed,  the  wax  wiped  or  melted  off,  and  the  characters 
scratched  on  the  waxed  surface  will  be  found  engraved  upon 
the  glass : 

(a)  CaF2  +  H2S04  =  CaS04 + 2HF. 

(6)  28HF  +  Na2Si307  •  CaSi307  =  2NaF + CaF2 + 6SiF4 + 14H20. 

Glass. 


112.  SILICA  AND  SILICATES. 

67.  SILICA  (Si02)  is  the  anhydrid  of  silicic  acid  (H4Si04). 
It  is  infusible,  insoluble  in  water  and  in  all  acids  except  HF. 
When  silica  is  heated  with  sulfuric  acid  and  calcium  fluorid 
in  a  leaden  or  platinum  vessel,  and  a  drop  of  water  in  the  loop 


102  QUALITATIVE  CHEMICAL  ANALYSIS. 

of  a  platinum  wire  held  in  the  escaping  gas,  the  water  will  become 
turbid,  due  to  the  formation  of  gelatinous  silicic  acid. 

(a)      4HF + Si02  =  SiF4 + 2H20. 

(6)  3SiF4+4H20  =  2H2SiF6+H4Si04. 

SILICATES. — These  salts  are  insoluble  in  water  except  the 
alkali  silicates.  They  are  decomposed  by  gaseous  hydrofluoric 
acid  or  a  mixture  of  sulfuric  acid  and  calcium  fluorid. 

68.  Hydrochloric    Acid    (HC1)   added  to  a  solution  of  an 
alkali  silicate  produces  a  gelatinous  precipitate  (scarcely  visible) 
of  H4Si04- 

69.  Ammonium  Chlorid  does  the  same. 

113.    ARSENIC  ACID  (H3As04)  AND  ARSENATES. 

70.  ARSENATES  behave  in  every  respect  exactly  like  phos- 
phates except  in  the  following  reaction. 

71.  Silver  Nitrate,  added  to  a  neutral  solution  of  an  arsenate, 
produces  a  reddish-brown  precipitate  of  silver  arsenate  (Ag3As04) : 

Na3As04 +3AgN03 = Ag3As04 +3NaN03. 

Phosphates  and  also  arsenites  treated  in  this  manner  pro- 
duce yellow  precipitates. 

72.  Magnesia   Mixture  added  to  a  neutral  or  ammoniac al 
solution  of  an  arsenate  produces  a  white  crystalline  precipitate  of 
ammonio-magnesium  arsenate  (NH4MgAs04)  (distinction  from 
arsenites) : 

K3As04 +MgCl2  +NH4C1  =  NH4MgAs04 +3KC1. 

73.  Potassium  lodid  added  to  an  acid  solution  of  an  arsenate 
will  reduce  it  with  a  separation  of  iodin : 

H3As04 +2HI  =  H3As03  +H20  +I2. 

This  test  will  detect  arsenic  acid  in  the  presence  of  arsenous 
acid,  but  is  useful  only  in  the  absence  of  oxidizing  agents,  as 
chromates,  nitrites,  manganates  and  ferric  salts. 


INORGANIC  BASES  AND  ACIDS.  103 

114.  ARSENOUS  ACID  (HsAs03)  AND  ARSENITES. 

74.  Hydrogen  Sulfid  added    to  a  solution  of  an  arsenite 
acidulated  with  hydrochloric  acid  produces  a  copious  yellow 
precipitate  of  As2S3: 

2H3As03  +3H2S= As2S3  +  6H20. 

If  the  solution  is  neutral  instead  of  acid,  H2S  does  not 
precipitate  the  sulfide,  but  colors  the  solution  yellow,  due 
to  the  formation  of  colloidal  As2S3. 

75.  Silver  Nitrate  added  to  a  neutral  solution  of  an  arsenite 
precipitates  yellow  silver  arsenite,  Ag3As03  (distinction  from 
arsenate) : 

K3As03  +3AgN03  =  Ag3As03  +3KN03. 

76.  Magnesia  Mixture  does  not  precipitate  arsenites   (dif- 
ference from  arsenates). 

77.  lodin  added  to  a  solution  of  an  arsenite  made  alkaline 
with   NaHCOs,   is  decolorized  and  oxidizes    the   arsenite  to 
arsenate: 

As203  + 14 + 2H20  =  4HI + As205. 

Other  tests  for  arsenic  and  arsenous  compounds  will  be 
found  under  tests  for  metals  of  Group  II. 

n5.          CHROMIC  ACID  AND  CHROMATES. 

78.  CHROMIC  ACID    (H2Cr04)   cannot  be  isolated,   but  its 
anhydrid,  Cr03,  is  well  known.     If  a  solution  of  this  anhydrid 
be  treated  with  dilute  hydrogen  dioxid  and  a  little  ether  added 
and  shaken  up  with  it,  the  perchromic  acid  formed  will  separate 
from  the  water  and  enter   the  ether,  forming  an  intense  blue 
solution.     This  test  is  exceedingly  delicate  and  may  be  applied 
to  chromates  after  slight  acidulation  with  sulfuric  acid.    It 
will  detect  1  part  of  K2Cr04  in  40,000  parts  of  water,  and 
may  be  used  also  as  a  very  delicate  test  for  H202. 


104  QUALITATIVE  CHEMICAL  ANALYSIS. 

79.  CHROMATES. — Alkali  chromates  and  chromates  of  mag- 
nesium and  calcium  are  soluble  in  water.    Most  other  chromates 
are  insoluble. 

Soluble  chromates  in  solution  are  yellow  in  color,  and  when 
treated  with  an  acid  turn  orange,  due  to  formation  of  dichromate. 

Soluble  dichromates  in  solution,  when  treated  with  an 
alkali  hydroxid,  turn  yellow. 

80.  Barium  Chlorid   added   to   a  solution  of   a    chromate 
precipitates-  yellowish-white  barium  chromate  (BaCr04)  which 
is  soluble  in  hydrochloric  acid : 

K2Cr04 + BaCl2  =  BaCr04 + 2KC1. 

With  potassium  dichromate  only  partial  precipitation  results, 
because  of  the  formation  of  hydrochloric  acid : 

K2Cr207 +2BaCl2  +H20  =  2BaCr04 +2KC1 +2HC1. 

The  addition  of  alkali  acetate  will,  however,  prevent  the 
solvent  action  of  HC1  on  the  precipitate,  and  insure  a  more 
complete  separation. 

81.  Lead  Acetate  added  to  a  neutral  or  acetic  acid  solution 
or  a  chromate  precipitates  yellow  lead  chromate  (PbCr04) : 

K2Cr04 +Pb  •  (C2H302)2  =  PbO04 +2KC2H302. 

This  precipitate  is  soluble  in  caustic  soda  solution,  but 
insoluble  in  NH4OH  and  in  acetic  acid. 

82.  Silver  Nitrate  added  to  a  neutral  solution  of  a  chromate 
precipitates  a  dark  red  silver  chromate   (Ag2Cr04)  which  is 
soluble  in  ammonium  hydroxid  and  in  nitric  acid : 

K2Cr04 +2AgN03 = Ag2Cr04  -f  2KN03. 

The  same  reagent  added  to  a  slightly  acid  chromate  solution 
precipitates  reddish-brown  Ag2Cr207. 


INORGANIC  BASES  AND  ACIDS. 


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106 


QUALITATIVE  CHEMICAL  ANALYSIS. 


117. 


GROUP  C.  SILVER  NITRATE  GROUP. 


STEP  IV. — To  another  portion  of  the  neutral  aqueous  solu- 
tion, add  silver  nitrate  T.S.,  and  observe  effect. 


Result. 


Indication. 


White  ppt.  insol.  in  dilute  nitric  acid; 
sol.  in  ammonia. 

White  ppt.  insol.  in  dilute  nitric  acid; 
insol.  in  ammonia. 


White  ppt.  sol.  in  dilute  nitric  acid. 

White  ppt.  sol.  in  dilute  nitric  acid; 

sol.  in  ammonia. 
White  ppt.  sol.  in  dilute  nitric  acid, 

ppt.  darkens  on  heating. 
White  ppt.  sol.  in  excess  of  sodium 

thiosulfate. 
Reddish-brown   ppt.    insol.    in    dilute 

nitric  acid. 

Reddish-brown  ppt.  sol.  in  dil.  HNO3. 

Yellow  ppt.  sol.  in  dil.  HNO3. 
Black  ppt.  sol.  in  dil.  HNO3. 


Chlorid. 

Bromid. 

lodid. 

Cyanid. 
|  Sulfocyanate. 
\  Ferrocyanid. 
f  Borate. 
1  Carbonate. 
1  Oxalate.          i 
I  Citrate. 
!  Tartrate. 

Meta  and  pyrophosphate. 

Sulfite. 

Hypophosphite. 
Thiosulfate. 

Ferricyanid. 

f  Chromate. 
\  Arsenate. 
/  Phosphate. 
1  Arsenite. 
Sulfid. 


CHARACTERISTIC  TESTS  FOR  THE  ACIDS  OF  GROUP  C. 

118.      HYDROCHLORIC  ACID  AND  CHLORIDS. 

HYDROCHLORIC  ACID  (HC1)  is  a  gas  and  occurs  in  commerce 
in  aqueous  solutions.     It  is  a  powerful  acid. 

83.  Manganese  Dioxid  added  to  hydrochloric  acid,  and  the 
mixture  heated,  gives  off  chlorin  gas : 

Mn02 + 4HC1 = MnCl2  +  2H20  +  C12. 

84.  Ammonium   Hydroxid   held    over  a  glass  rod  near  the 
mouth  of  a  vessel  containing  hydrochloric  acid,  produces  dense 
white  clouds  of  NH4C1. 


INORGANIC  BASES  AND  ACIDS.  107 

85.  Silver   Nitrate  produces  a  curdy  white  precipitate  of 
AgCl,  soluble  in  NELiOH  and  reprecipitated  upon  acidulation 
with  HN03. 

86.  CHLORIDS. — Silver  Nitrate  added  to  a  solution  of  a  chlorid 
in  the  presence  of  nitric  acid  gives  a  curdy  white  precipitate 
which  is  soluble  in  ammonium  hydroxid  and  reprecipitated 
upon  acidulation  with  nitric  acid: 

NaCl + AgN03 = AgCl + NaN03. 

87.  Manganese  Dioxid  and  Concentrated  Sulfuric  Acid  added 
to  a  chlorid  and  the  mixture  heated,  evolves  chlorin  gas,  which 
may  be  recognized  by  its  odor,  and  its  bleaching  power  on 
moist  litmus  or  indigo  paper,  and  by  its  liberating  iodin  from 
iodids,  and  turning  starch-iodid  paper  blue: 

Mn02  +  2H2S04  +  2NaCl  =  MnS04  +  Na2S04  +  2H20 + C12. 

88.  Lead  acetate  produces  a  white  ppt.  soluble  in  hot  water. 

119.  HYDROBROMIC  ACID  (HBr)  AND  BROMIDS. 

89.  Silver  Nitrate  added  to  a  solution  of  a  bromid  precipitates 
dirty-white  AgBr  insoluble  in  nitric  acid,  sparingly  soluble  hi 
strong  ammonia  water,  but  insoluble  in  dilute  (5  per  cent.) 
ammonia  water. 

90.  Chlorin  Water  added  drop  by  drop  to  a  solution  of  a 
bromid  liberates  bromin.    If  a  few  drops  of  chloroform  be 
added  to  this  mixture  and  shaken,  the  chloroform  will  dissolve 
the  liberated  bromin,  forming  a  golden  yellow  or  reddish  colored 
bead,  which  settles  to  the  bottom  of  the  test-tube.    The  color 
produced  depends  upon  the  amount  of  bromin  present. 

120.  HYDRIODIC  ACID  (HI)  AND  IODIDS. 

91.  Silver  Nitrate  added  to  a  solution  of  an  iodid  precipitates 
yellow  Agl,  insoluble  in  nitric  acid  and  only  very  sparingly 
soluble  in  ammonia  water. 

92.  Chlorin  Water  reacts  with  iodids  in  same  manner  as  it 
does  with  bromids,  the  liberated  iodin  dissolving  hi  the  chloro- 


108  QUALITATIVE  CHEMICAL  ANALYSIS. 

form,  forming  a  violet  bead.  Free  iodin  may  also  be  identified  by 
adding  starch  paste,  with  which  it  strikes  a  blue  color.  In 
this  test,  as  in  the  corresponding  test  for  bromid,  care  must  be 
taken  to  avoid  adding  an  excess  of  chlorin  water,  otherwise 
colorless  iodic  acid  (HI03)  will  be  formed. 

93.  Mercuric  Chic-rid  added  to  an  iodid  precipitates  red 
HgI2,  which  dissolves  as  long  as  the  iodid  is  in  excess,  but 
remains  precipitated  if  the  mercuric  chlorid  is  in  excess  : 


HgCl2  +  2KI  =  HgI2  +  2KC1, 
HgI2+2KI  =  K2HgI4. 


121.  SULFOCYANATES     (Thiocyanates)  (RONS). 

94.  Silver  Nitrate,  added  to  a  solution  of  a  sulfocyanate, 
precipitates  white  silver  sulfocyanate,  insoluble  in  dilute  nitric 
acid  and  in  ammonium  hydroxid : 

KCNS  + AgN03 = AgCNS.  +  KN03. 

95.  Ferric  Salts  brought  in  contact  with  a  solution  of  sulfo- 
cyanate  gives  a  blood-red  coloration  due  to  the  formation  of 
Fe(CNS)3.    This  color  is  destroyed  by  mercuric  chlorid  (dis- 
tinction from  meconate)  but  is  not  destroyed  by  hydrochloric 
acid  (distinction  from  acetate). 

122.  FERROCYANIDS  (R'4Fe(CN)6). 

96.  Silver    Nitrate  added   to   a  solution  of  a  ferrocyanid 
produces  a  white  gelatinous  precipitate  of  Ag4Fe(CN)6  insoluble 
in  dilute  nitric  acid  and  in  ammonium  hydroxid,  unless  heated : 

K4Fe  (CN)  6 + 4AgN03  -  Ag4Fe  (CN)  6 + 4KN03. 

97.  Ferric     Salts   produce   with   slightly   acid   solutions   of 
ferrocyanids  a  blue  precipitate  Fe4(Fe(CN)6)3  Prussian  blue. 

98.  Copper    Sulfate  added  to  a  solution  of  a  ferrocyanid 
produces  a  reddish-brown  precipitate  of  Cu2Fe(CN)6. 


INORGANIC  BASES  AND  ACIDS. 


109 


123.  FERRICYANIDS  (R'3Fe(CN)6). 

99.  Silver  Nitrate  produces  with  ferricyanids  a  reddish-brown 
precipitate   (AgsFe(CN)6)  insoluble  in  nitric  acid  but  soluble 
in  ammonium  hydroxid. 

100.  Ferrous   Sulfate  or  any  ferrous  salt  gives  a  blue  precip- 
itate (Fe3(Fe(CN)6)2Turnbuirs  blue)  insoluble  in  acids.     Ferric 
salts  give  no  precipitate  but  a  brownish  coloration. 

124.     CHART  FOR  THE  OBSERVATION  OF  THE  REACTIONS  OF 
THE  ACIDS  OF  THE  SILVER  NITRATE  GROUP  (C). 


AgNO3. 

Pb(C2H302)2. 

Chlorine  Water. 

Special  Tests. 

Chlorid, 
-Cl. 

White   ppt. 
Soluble     i  n 
NH4OH. 

White  ppt. 
Soluble  in 
hot  water. 

MnO2H2SO4  = 
Cl  liberated. 

Bromid, 
—  Br 

White  ppt. 
Sparingly 
soluble      i  n 
strong 
NH4OH.  In- 
soluble     i  n 
HNO3. 

White  ppt. 
Soluble    i  n 
hot  water. 

Liberates    Br 
Add   CHC13 
A  golden  yel- 
low color  is 
imparted  to 
the  latter. 

lodid, 
j 

Yellow    ppt., 
very  sparing- 
ly soluble  in 
NH4OH.  In- 
soluble     i  n 
HNO3. 

Yellow  ppt. 
Soluble  i  n 
hot  water. 

Liberates     I, 
which  turns 
starch  paste 
blue. 

HgCl2  =  red 
ppt.    soluble 
in   excess   of 
the  iodid. 

Sulfocyanate, 

—  CNS. 

White  ppt. 
Insoluble  in 
NH4OH.  In- 
soluble i  n 
diluteHNO3. 

White  ppt. 

Ferric  salts 
give   blood 
red  color  de- 
troy  ed      b  y 
HgCl2,   but 
not  by  HC1. 

Ferrocyanid, 

—  4Fe(CN)6 

White  ppt. 
Soluble  i  n 
hot  NH4OH. 

White  ppt. 

Acidified     so- 
lution +ferric 
salt  =  blue. 
CuSO«=  red- 
dish    brown 
ppt. 

Ferricyanid, 

—  3Fe(CN)6 

Reddish- 
brown  ppt. 
Soluble  i  n 
NH4OH,not 
in  HNO3. 

No  ppt. 

Acidified     so- 
lution+  fer- 
rous   salt  = 
blue. 

110  QUALITATIVE  CHEMICAL  ANALYSIS. 

125.  GROUP  D.  DEFLAGRATING  GROUP. 

STEP  V.  —  A  portion  of  the  original  dry  substance  or  the 
residue  on  evaporation,  is  placed  in  a  shallow  concavity  on  a 
piece  of  charcoal  and  heated  by  means  of  a  blow-pipe  flame.  A 
more  or  less  violent  deflagration  indicates  nitrate,  nitrite,  chlor- 
ate, br  ornate,  Mate,  hypophosphite  or  permanganate. 

CHARACTERISTIC  TESTS  FOR  ACIDS  OF  GROUP  D. 

126.  NITRIC  ACID  AND  NITRATES. 

NITRIC  ACID  (HNO)3.  A  powerful  corrosive  acid  liquid. 
It  fumes  in  the  air  and  dissolves  most  metals. 

101.  A  piece  of  copper  is  put  into  a  test-tube  with  some  nitric 
acid.    Effervescence    takes    place    and    orange-red    fumes    of 
N204  are  evolved. 

102.  A  quill  immersed  in  nitric  acid  is  stained  yellow;   this 
color  is  intensified  on  touching  the  stained  quill  with  an  alkali. 

103.  NITRATES.  —  Copper  foil  or  filings  added  to  a  nitrate  and 
the  mixture  then  heated  with  sulfuric  acid,  produces  orange- 
red  fumes  of  N204  : 

(a)  KN03+H2S04=KHS04+HN03. 

(6)  3Cu  +  8HN03    = 

(c)  N202  +  02          =N204. 


104.  Ferrous  Sulfate  in  the  form  of  a  freshly-prepared  solu- 
tion is  mixed  with  an  equal  volume  of  a  saturated  solution 
of  a  nitrate,  and  the  mixture  floated  upon  concentrated  sulfuric 
acid  in  a  test-tube;  a  brown  ring  will  form  at  line  of  contact. 

105.  When  ignited,  nitrates  evolve  oxygen,  KN03  =  KN02  +  0. 

127.  NITROUS  ACID  AND  NITRITES. 

NITROUS  ACID  (HN02).  —  Commercial  nitrous  acid  is  nitric 
acid  containing  nitrous  anhydrid.  It  has  a  yellowish  color 
and  evolves  reddish  fumes. 


INORGANIC  BASES  AND  ACIDS.  Ill 

NITRITES.— -All  nitrites  are  soluble  in  water,  silver  nitrite 
only  sparingly. 

106.  Sulfuric  Acid  when  dilute,  decomposes  nitrites  (but 
not  nitrates)  with  evolution  of  reddish  fumes.  The  gas  evolved 
in  this  reaction  is  N202,  which  in  contact  with  the  air  is  oxidized 
to  N204: 


(a)  2NaN02  +  H2S04=Na2S04+2HN02. 
(6)  3HN02  =  HN03+H20  +  N202. 
(c)  N202+02  =  N204. 

107.  Potassium  lodid  and  Starch  Solution,  when  added  to  a 
solution  of  a  nitrite,  and  the  mixture  acidified  with  acetic  acid 
produces  a  blue  color: 

2HN02  +  2HI  =  I2 + 2H20 + N202. 

108.  Ferrous   Sulfate  T.S.   mixed  with  an  equal  volume  of 
a  solution  of  a  nitrite  when  floated  upon  concentrated  acetic 
acid  in  a  test-tube,  produces  a  dark-brown  ring  at  the  line 
of    contact.    This    test    distinguishes   nitrites   from  nitrates, 
the  latter  requiring   sulfuric  acid  to  produce  the  described 
effect. 

128.  CHLORATES  (R'C103). 

109.  When  ignited,  chlorates  evolve  oxygen  and  leave  a  residue 
of  the  chlorid  of  the  metal.    KC103  =  KC1+03.    Treat  residue 
as  under  paragraph  118. 

110.  Concentrated  Sulfuric  Acid  is  warmed  and  treated  with 
a  crystal  of  potassium  chlorate.    The  chlorate  is  decomposed, 
producing  (C102) ,  a  greenish-yellow  gas  which  explodes  violently. 

Caution.    Perform  this  test  with  great  care  so  as  to  avoid 
harm  to  yourself  and  to  your  neighbor. 

129.  BROMATES  and  IODATES,  like  chlorates,  are    reduced 
when  heated,  evolving  oxygen  and  leaving  a  residue  respectively 
of  bromid  and  iodid.   Treat  residue  as  under  paragraphs  119  and 


112  QUALITATIVE  CHEMICAL  ANALYSIS. 

120  respectively.    Like  chlorates,  these  salts  deflagrate  when 
heated  on  charcoal. 

Dilute  Sulfurous  Acid  liberates  respectively  bromin  and 
iodin;  which  can  be  recognized  by  the  CHC13,  bead. 

130.  PERMANGANATES  (R'Mn04). 

111.  Color. — The  color  of  permanganate  solutions  is  violet 
or  pink  according  to  the  degree  of  concentration. 

The  color  is  destroyed  by  adding  oxalic  acid,  and  warming, 
or  by  heating  with  hydrochloric  acid  and  adding  alcohol  or 
glycerin. 

112.  When  ignited,  permanganates  yield  oxygen. 

131.  HYPOPHOSPHITES  (RTH202). 

113.  When  the  dry  salt  is  heated  in  a  test-tube  or  porcelain 
dish  phosphoretted  hydrogen  (PH3)  is  evolved,  which  bursts 
into  flame,  a  residue  of  pyrophosphate  being  left. 

This  test  should  not  be  made  on  a  platinum  foil  because  the 
latter  will  be  destroyed  by  it. 

114.  Silver  Nitrate  added  to  a  solution  of  a  hypophosphite 
gives  a  white  precipitate  which  rapidly  turns  brown,  owing 
to  reduction  to  metallic  silver. 

115.  Mercuric  Chlorid,  added  to   a   hypophosphite  solution 
slightly  acidulated  with  hydrochloric  acid,  gives  a  precipitate 
of  calomel  (Hg2Cl2)  which  darkens  on  heating,  owing  to  reduction 
to  metallic  mercury. 

116.  Free  Hypophosphorous  Acid,   warmed    to   55°  C.  with 
copper  sulfate   solution  gives   a  reddish-black    precipitate   of 
copper  hydrid  (Cu2H2)  which  is  reduced  to  metallic  copper  upon 
boiling. 

This  test  may  be  applied  to  hypophosphites,  by  first  removing 
the  metallic  base.  If  the  base  is  calcium  precipitate  it  with 
oxalic  acid;  if  barium,  use  sulfuric  acid;  if  a  heavy  metal  use 
hydrogen  sulfid. 


INORGANIC  BASES  AND  ACIDS. 


113 


132.    CHART  FOR  THE  OBSERVATION  OF  REACTIONS  OF  ACIDS 
OF  DEFLAGRATING  GROUP  "D." 


Heating  Dry  Sub- 
stance in  a  Test-tube. 

H2S04. 

Special  Testa. 

NITRATES, 
—  N03 

Evolves  O,  which 
kindles  glowing 
wood. 

/ 

+Cu  foil  and  heat 
with  H2SO4  = 
fumes  of  N2O4. 
FeSO4  (freshly  pre- 
pared) and  float  on 
H2SO4  =  brown  ring 
at  contact. 

NITRITES, 
—  NO2 

Evolves,  O,  N,  and 
nitrogen  dioxid. 

+dil.  H2SO4  =  evo- 
lution   of    N2O2, 
which  is  oxidized 
to  N204. 

FeSO4+equal     vol. 
of  nitrite  floated  on 
HC2H3O2  =  brown 
ring  at  line  of  con- 
tact.   (Nitrates  re- 
quire H2SO4).    KI 
+HC2H302+ 
starch  =  blue. 

CHLORATES, 
—  C1O3. 

Evolves  O  and 
leaves  a  chlorid  ol 
metal,  which  test. 

Explosion    with 
production  of  a 
greenish-yellow 
gas. 

BROMATES, 
—  Br03. 

Evolves  O  and 
leaves  a  bromid 
of  the  metal, 
which  test. 

Dil.  H2S04  liber- 
ates Br,  which 
gives  a  reddish 
bead  with  CHC13. 

lODATES,  —  IO3. 

Evolves  O  and 
leaves  an  iodid 
of  metal,  which 

test. 

Dil.  H2SO4  liber- 
ates I,  which 
turns  blue  with 
starch. 

PERMANGAN- 
ATES, —  MnO4. 

Evolves  O,  which 
kindles  glowing 
wood. 

Color  of  solution  is 
violet  and  is  de- 
stroyed by  oxalic 
acid  or  by  heating 
with  HC1  and  ad- 
ding alcohol  or 
glycerin. 

HYPOPHOS- 

PHITES, 

—  PH2O2. 

Evolves    PH3, 
which  bursts  into 
flame. 

AgNO3  =  white  ppt., 
turns      brown. 
HgCl2+HCl  = 
white  ppt.    Dark- 
ens    on     heating. 
Free  acid+CuSO4, 
warmed  to  55°  C., 
reddish-black  ppt. 

114  QUALITATIVE  CHEMICAL  ANALYSIS. 

CHARACTERISTIC  TESTS  FOR  THE  ORGANIC  ACIDS. 
133.  GROUP  E.    FERRIC  CHLORID  GROUP. 

STEP  VI. — To  another  portion  of  the  neutral  aqueous  solu- 
tion add  ferric  chlorid  T.S.,  and  observe  effect. 


Result. 


Indication. 


Red  Colored  Solution.     No  ppt. 
Color  gradually  disappears. 
Color  is  discharged  by  HgCl2  and 

HC1. 
Color  is  discharged  by  HgCl2  but 

not  by  HC1. 
Color  changed  to  deep  bluish-black 

by  ammonia. 

Color  is  not  discharged  by  HgCl2. 
Color  is  fault. 
Color  is  destroyed  by  heat. 

Violet  colored  solution. 

Pale  green  solution. 

A  darkening  of  the  solution,  no  ppt. 

Black  ppt. 

Dark  blue  ppt. 

Buff  or  flesh-colored  ppt. 

Reddish-brown  ppt. 
Pink  to  brownish-red  ppt. 


Thiosulfate. 
Acetate. 

Sulfocyanate. 
Pyrogallate. 

Meconate. 

Trichloracetic. 

Sulfite. 

f  Salicylate. 

|  Carbolate. 

[  Phenolsufonate. 
Citrate. 
Ferricyanid. 

{  Sulfid. 

\  Gallate. 

I  Tannate. 
Ferrocyanid. 
Benzoate. 

f  Carbonate. 

\  Hydroxid. 

[  Chromate. 
Succinate. 


CHARACTERISTIC  TESTS  FOR  ACIDS  OF  GROUP  E. 
134.  ACETIC  ACID  AND  ACETATES. 

117.  ACETIC  ACID  (HC2H302)  is  recognized  by  its  odor  of 
vinegar. 

118.  ACETATES. — All   normal   acetates   are   soluble.    Some 
basic  acetates,  as  ferric  subacetate,  and  aluminum  subacetate, 
are    practically   insoluble.     On   ignition,    acetates   decompose, 
with  little  or  no  charring,  and  evolve  an  inflammable  gas. 

Alkali  acetates  are  converted  on  ignition  into  carbonates. 


INORGANIC  BASES  AND  ACIDS.  115 

Other  acetates  are  converted  by  ignition  into  oxids,  or  reduced 
to  the  metal. 

119.  Sulfuric  Acid,  heated  with  an  acetate,  liberates  acetic 
acid,  recognized  by  its  odor  of  vinegar: 

NaC2H302 + H2S04 = NaHS04 + CH3COOH. 

120.  Alcohol   and   Strong   Sulfuric  Acid,  gently  heated  with 
an  acetate,  yields  acetic  ether,  recognized  by  its  odor  of  apples: 

CHaCOOH  +  C2H5OH = CH3COOC2H5 + H20. 

121.  Ferric  Chlorid    produces  with  acetates  a  red-colored 
solution    (ferric    acetate)    Fe2(C2H302)6.    If   this   solution   is 
largely  diluted  with  water  and  boiled,  a  precipitate  of  basic 
ferric  acetate  (Fe(OH)(C2H302)2)  is  produced.    The  red  color 
first  produced  is  discharged  by  both  HC1  and  HgCl2  (distinction 
from  sulfocyanates). 


135.        BENZOIC  ACID  AND  BENZOATES. 

BENZOIC  ACID  (HC7H502)  occurs  in  yellowish-white  lustrous 
scales  or  friable  needles  having  a  slight  benzoin-like  odor. 
It  is  only  slightly  soluble  hi  water  but  readily  soluble  in 
alcohol. 

122.  Heated  in  a  tube  open  at  both  ends  it  sublimes,  and 
evolves  an  irritating  odor. 

123.  Slaked  Lime,  mixed  with  one-third  its  weight  of  benzoic 
acid  and  heated  in  a  test-tube,  evolves  benzene. 

124.  Ferric   Chlorid,  added  to  a  neutralized  solution  of  ben- 
zoic acid  in  alkali  hydroxid  gives  a  flesh-colored  precipitate  of 
ferric  benzoate. 

125.  BENZOATES.— When  ignited,  they  char  and  leave  a  residue 
of  carbonate  (see  Citrates). 

126.  Ferric  Chlorid,  added  to  an  aqueous  solution  of  a  ben- 
zoate, gives  a  flesh-colored  precipitate. 


116  QUALITATIVE  CHEMICAL  ANALYSIS. 

127.  Dilute   Sulfuric    or    Hydrochloric   Acid,    added  to  an 
aqueous  solution  of  a  benzoate,  produces  a  white  precipitate  of 
benzoic  acid. 

128.  Silver  Nitrate  produces  a  white  ppt.  soluble  in  hot  H20 
and  NH4OH. 


136.     SALICYLIC  ACID  AND    SALICYLATES. 

SALICYLIC  ACID  (HC7H503)  occurs  in  white  crystalline  pow- 
der or  prisms.     It  is  readily  soluble  in  alcohol,  but  not  in  water. 

129.  SALICYLATES,  upon  heating,  behave  like  the  previously 
described  organic  salts. 

130.  Ferric  Chlorid,  added  to  an  aqueous  solution,  produces 
an  intense  bluish- violet  coloration. 

131.  On  adding  to  a  small  portion  of  salicylic  acid,  or  a  salicy- 
late,  in  a  test-tube,  some  concentrated  sulfuric  acid,  and  then 
continuously  in  drops  some  methyl  alcohol,  and  heating  the  mix- 
ture to  boiling,  an  odor  of  oil  of  wintergreen  (methyl  salicylate)  is 
produced. 

132.  Copper  Sulfate  Solution  added  to  an  aqueous  solution  of 
a  salicylate  gives  a  green  coloration. 

133.  Dilute    Sulfuric   Acid  precipitates  salicylic  acid  out  of 
solutions  of  salicylates. 

134.  Silver  Nitrate  gives  a  white  ppt.  soluble  in  hot  water. 


INORGANIC   BASES  AND  ACIDS.  117 

137.  TANNIC,  GALLIC,  AND  PYROGALLIC  ACIDS. 

TANNIC  ACID,  HCi4H909  (C13H907COOH). 

GALLIC  ACID,  HC7H505 + H20  (C6H2(OH) 3COOH + H20) . 

PYROGALLIC  ACID,  C6H603  (C6H3(OH)3). 


Reagent. 

Tannic  Acid. 

Gallic  Acid. 

Pyrogallic  Acid. 

135.  (a)  Ferric 
Chlorid. 

A    bluish  -  black 
coloration  or  ppt. 

Same  effect. 

Brownish  -  red 
solution,  changed 
to  deep  bluish- 
black  upon  addi- 
tion of  NH4OH. 

136.  (6)  Pure  Fer- 
rous Sulfate. 

Neither  color  nor 
ppt. 

A  bluish-black 
solution. 

(c)  Lime   water 
(in  small  amount) 

(In       moderate 
excess). 

(In     large     ex- 
cess.) 

A    pale,    bluish- 
white    ppt.    which 
does    not    dissolve 
on  shaking. 
A  more  cuprous 
and     deeper     blue 
ppt. 

Imparts  to  liquid 
a  pale  pink  tint. 

Ppt.  dissolved  on 
shaking. 

Ppt.    is    perma- 
nent, and  the  solu- 
tion    is     blue     by 
reflected  light  and 
green     by     trans- 
mitted light. 
Liquid     becomes 
pink. 

A  purple  solu- 
tion becoming 
brown  by  oxida- 
tion. 

137.  (d)  Solu- 
tions    of    gelatin 
albumen,    starch, 
most  alkaloidsand 
glucosides. 

A  ppt. 

No  ppt. 

No  ppt. 

138.         PHENOLSULFONATES  (Sulfocarbolates) 

(R'C6H4(OH)S03). 

Heated  above  100°  C.  phenolsulfonates  char,  emit  inflammable 
vapors  with  an  odor  of  phenol,  and  leave  a  residue  of  sulfate. 

138.  Ferric   Chlorid  added  to  a  solution  of  a  phenolsulfonate 
gives  a  pale  violet  color. 

139.  Barium    Chlorid  gives  no  precipitate,  but  if  a  portion 
of  the  salt  is  ignited  and  the  residue  dissolved  in  water,  barium 
chlorid  will  produce  a  white  precipitate. 


118  QUALITATIVE  CHEMICAL  ANALYSIS. 

139.  PHENOLATES. 

Ferric  Chlorid  gives  a  violet  color. 

Heated  with  sulfuric  acid,  phenolates  give  an  odor  of  phenol. 

140.  MECONIC  ACID  (H2C7H207  +  3H20). 

140.  MECONATES. — Neutral  Ferric  Chlorid  Solution  produces  a 
red  color  with  meconic  acid  or  meconates.    This  color  is  not 
discharged  by  HgCl2,  but  is  bleached  by  dilute  HC1  (distinction 
from  sulf ocyanate) . 

Compare  with  acetate. 

141.  Silver  Nitrate  gives  a  yellowish  ppt.  soluble  in  HN4OH. 

141.  SUCCINIC  ACID  (H2C4H404). 

Succinic  acid  does  not  char  with  strong  hot  sulfuric  acid. 
Sublimes  in  a  tube  open  at  both  ends  without  giving  off  an 
irritating  odor  (difference  from  benzoic  acid). 

142.  SUCCINATES. — Ferric  Chlorid  gives  a  brownish-red  pre- 
cipitate Fe2(C4H404)3. 

143.  Barium    Chlorid    gives   no   precipitate   unless   alcohol 
and  ammonium  hydroxid  be  added,  when  a  white  precipitate 
is  formed  (difference  from  benzoic  acid). 

144.  Lead  Acetate  gives  a  white  precipitate  soluble  in  suc- 
cinic  acid  and  excess  of  reagent. 

145.  Silver  Nitrate  gives  in  neutral  solutions  a  white  ppt« 
soluble  in  NH4OH. 

142.       TRICHLORACETIC  ACID  (HC2C1302). 

146.  Is  a  deliquescent  crystalline  solid,   soluble  in  water, 
alcohol  and  ether. 

147.  The  aqueous  solution  is  decomposed  on  boiling,  forming 
chloroform  and  carbon  dioxid. 

148.  On  heating  with  Potassium  Hydroxid  T,S.,  it  is  decom- 
posed, forming  chloroform  and  potassium  carbonate. 

149.  Ferric   Chlorid,  added  to  an  aqueous  solution  of  trichlor- 
acetic  acid  develops  a  faint  reddish  color. 


INORGANIC  BASES  AND  ACIDS. 


119 


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QUALITATIVE  CHEMICAL  ANALYSIS. 


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PHENOLATE! 

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MECONATE 
—  2C7H2Ov3H 

SUCCINATE 
—  C4H404. 

TRICHLORACET: 
—  C2C13O2. 

INORGANIC  BASES  AND  ACIDS. 


121 


144. 


GROUP  F.    CALCIUM  CHLORID  GROUP. 


STEP  VII. — To  another  portion  of  the  neutral  aqueous  solu- 
tion, add  some  calcium  chlorid  T.S.,  and  observe  effect. 


Result. 


Indication. 


A  white  ppt.  is  produced. 
Soluble  in  NH4C1  Sol. 


Sol.  in  acetic  acid. 

Insol.  in  acetic  acid. 

The  ppt.  chars  when  heated. 

Sol.  in  NaOH,  reprecipitated  on  boil- 
ing. An  excess  of  reagent  must 
be  added  to  obtain  this  ppt. 

Sol.  in  much  water. 

White  ppt.  in  presence  of  alcohol. 


( Borate. 
\  Carbonate. 
I  Citrate. 

Borate. 

Sulfite. 

Carbonate. 

Phosphate. 

Citrate. 
Oxalate. 
/  Tartrate. 
\  Citrate. 
Tartrate. 


Sulfate. 
Malate. 


145.  CITRIC  ACID  AND  CITRATES. 

CITRIC  ACID  (H3C6H507)  occurs  in  colorless  crystals  having 
a  distinct  acid  taste,  deliquescent  in  moist  air  but  efflorescent 
when  exposed  in  dry  air.  Soluble  in  water  and  in  alcohol. 

150.  On  igniting  it  slowly  it  is  gradually  decomposed,  without 
emitting  an  odor  of  burning  sugar   (difference  from  tartaric 
acid). 

151.  Its  addition  to  a  solution  of  a  ferric  salt  prevents  precip- 
itation of  ferric  hydroxid  on  adding  ammonium  hydroxid. 

152.  Upon  adding  to  a  solution  of  citric  acid  sufficient  lime 
water  to  render  the  mixture  alkaline,  the  liquid  remains  clear. 
Upon  boiling  this  for  one  minute  it  becomes  opaque,  through 
precipitation  of  calcium  citrate,  which  redissolves  on  cooling. 

153.  CITRATES. — Upon  healing  citrates  char.    The  citrates  of 
the  alkali  and  alkali  earth  metals  char,  and  are  reduced  to 
carbonates.     Citrates   of   most   other  metals   are  reduced   by 
ignition  to  oxids,  while  silver  citrate  is  reduced  to  the  metal. 


c&$ 


122  QUALITATIVE  CHEMICAL  ANALYSIS. 

154.  Calcium  Chlorid  Solution,  added  to  a  cold  solution  of  a  cit- 
rate made  slightly  alkaline  with  ammonia  water,  gives  no  precip- 
itate, until  boiled,  when  a  white  granular  precipitate  is  produced. 

155.  Strong     Sulfuric   Acid   heated   with   a   citrate   slowly 
blackens  it,  and  evolves  a  slight  odor  resembling  burning  sugar. 

146.       TARTARIC  ACID  AND  TARTRATES. 

156.  TARTARIC  ACID  (H2C4H406)  is  a  strong  organic  acid.    It 
is  freely  soluble  in  water  and  in  alcohol.     When  heated  it  chars, 
and  finally  burns  away.     Heated  with  strong  sulfuric  acid,  it  is 
charred,  and  evolves  an  odor  resembling  that  of  burnt  sugar. 

157.  A  concentrated  solution  of  tartaric  acid,  when  treated 
with  potassium  acetate,  gives  a  white  precipitate  of  potassium 
bitartrate.    The  addition  of  alcohol  facilitates  this  precipitation: 

H2C4H406  +  KC2H302  =  KHC4H406 + HC2H302. 

158.  TARTRATES. — Tartrates  char  when  heated. 

159.  Silver  Nitrate  added  to  a  solution  of  a  normal  tartrate, 
precipitates  white  silver  tartrate  (Ag2C4H4Oe)  readily  soluble  in 
ammonium  hydroxid.     If  this  ammoniacal  solution  be  gently 
heated,  the  silver  will  deposit  on  the  sides  of  the  test-tube, 
forming  a  mirror. 

160.  Silver  nitrate  does  not  react  with  free  tartaric  acid. 

161.  Calcium   Chlorid  added  to  a  concentrated  solution  of  a 
neutral  tartrate  precipitates  white  crystalline  calcium  tartrate 
(CaC4H406).    This  precipitate,  when  washed  with  water,  dis- 
solves in  cold  sodium  hydroxid  solution.     If  this  solution  is 
boiled  CaC4H406  is  again  precipitated  in  gelatinous  form,  and 
redissolves  on  cooling.    The  reagent  must  be  added  in  excess  to 
obtain  this  precipitate,  and  ammonium  salts  must  be  absent. 

This  test  differentiates  tartrates  from  citrates. 

162.  Potassium    Acetate    and    other  Potassium  Salts  when 
added  to  a  solution  of  a  tartrate  slightly  acidified  with  acetic 
acid,  gives  a  crystalline  white  precipitate  of  KHC4H406.    The 
precipitation  is  facilitated  by  stirring  and  by  the  addition  of 
alcohol. 


INORGANIC  BASES  AND  ACIDS. 


123 


163.  Neutral  solutions  of  tartrates  are  not  precipitated  by 
potassium  salts. 

164.  Ferric  chlorid  gives  in  neutral  solutions,  a  yellow  crys- 
talline ppt.  on  warming. 

147.  MALIC  ACID  (H2C4H405). 

165.  MALATES. — Calcium  Chlorid,  added  to  a  neutral  aqueous 
solution  of  a  malate,  gives  no  precipitate  because  calcium  malate 
is  soluble  in  water.    The  addition,  however,  of  even  a  small 
quantity  of  alcohol  causes  a  precipitation  of  a  calcium  malate. 
Calcium  malate  dissolves  when  boiled  with  lime  water  (difference 
from  citrate). 

166.  Hot  strong  Sulfuric  Acid  chars  malic  acid  very  slowly 
(difference  from  tartaric  acid). 

167.  Lead  Acetate  gives  a  white  ppt.  soluble  in  hot  water. 

148.  CHART  FOR  THE  OBSERVATION  OF  THE  REACTIONS  OF 
THE  ACIDS  OF  Cad*  GROUP.  GROUP  F. 


Citrates. 

Tartrates. 

Malates. 

CaCl2  and 
NH4OH. 

Cold  =  no    ppt. 
Boiled  =  white 
granular  ppt. 

White  ppt.  soluble  in 
NaOH.  Boiled  =  a 
gelatinous  ppt.  redis- 
solves  on  cooling. 

In  neutral  solutions 
=no  ppt.  Add  al- 
cohol =  ppt.  soluble 
in  lime  water. 

HEAT. 

Chars. 

Chars. 

Chars. 

H2S04 

Blackens    and 
evolves    a    slight 
odor  resembling 
burning  sugar. 

Chars  and  evolves  odor 
of  burning  sugar. 

Chars  very  slowly. 

AgN03 

White  ppt.  soluble  in 
NH4OH.  If  heated, 
a  silver  mirror  will 
deposit  on  sides. 

POTASS. 

ACETATE 

-j-HC2H3O2=  white 
ppt.     especially     in 
presence  of  aclohol. 

FeCl3 

Yellow  crystalline  ppt. 
on  warming. 

LEAD  ACE- 
TATE. 

White  ppt.  soluble 
in  hot  H2O. 

124  QUALITATIVE  CHEMICAL  ANALYSIS. 

149.  GROUP  G.    UNCLASSIFIED  GROUP. 

STEP  VIII. — Unless  contra-indicated,  make  individual  tests 
for  acids  not  mentioned  in  the  foregoing  steps,  as  for  instance, 
lactic,  oleic,  stearic,  valeric,  etc. 

150.  LACTIC  ACID  AND  LACTATES. 

LACTIC  ACID  (HCsHsOs).    A  colorless  syrupy  liquid. 

168.  Potassium  Permanganate,  added  to  a  mixture  of  equal 
parts  of  lactic  and  sulfuric  acids  and  gently  heated,  evolves 
odor  of  aldehyde. 

169.  On  heating  above  160°  C.,  the  acid  emits  inflammable 
vapors  and  burns  away  with  a  pale  flame. 

170.  Heated  with  Sulfuric  Acid,  it  gives  off  a  large  quantity 
of  pure  CO. 

171.  Strong  solutions  of  an  alkali  lactate,  when  boiled  with 
HgNOs,  deposit  pink  mercurous  lactate,  HgCsHsOs. 

172.  Silver  nitrate  solution  when  heated  with  lactic  acid, 
will  be  reduced  and  metalli<  silver  will  deposit  slowly. 

151  OLEIC  ACID  AND  OLEATES. 

OLEIC  ACID  (HCi8H3302)  is  an  oily  liquid  of  a  brownish 
or  yellowish  color  which  when  cooled  to  below  4°  C.  solidifies. 
It  is  insoluble  in  water  but  is  soluble  in  ether,  chloroform, 
alcohol,  benzin  and  fixed  and  volatile  oils. 

173.  OLEATES  of  sodium  and  potassium  are  soluble  in  water. 
Other  oleates  are  not.    Acid  oleates  are  liquid  and  dissolve 
readily  in  absolute  alcohol  and  ether.    The  alcoholic  solution 
is  acid  in  reaction. 

174.  Oleates  do  not  separate  out  from  the  above-named  sol- 
vents when  a  hot  solution  is  cooled  (difference  from  stearates 
and  palmitates). 

175.  Lead  Acetate  added  to  an  aqueous  solution  of  an  oleate 
gives  a  white  precipitate  of  Pb(Ci8H3302)2  which  is  soluble 


INORGANIC  BASES  AND  ACIDS.  125 

in  ether  (distinction  from  stearate).    Stearate  and  oleate  may  be 
separated  one  from  the  other  in  this  way. 

'152.         STEARIC  ACID  AND  STEARATES. 

176.  STEARIC   ACID    (HCi8H3502)    is   a   white  fatty  solid. 
Melts  on  heating  and  is  soluble  in  boiling  alcohol  and  in  ether. 
The  alcoholic  solution  is  acid  in  reaction. 

177.  If   stearic   acid   be   dissolved   in  potassium  hydroxid 
solution,  and  the  solution  carefully  neutralized,  the  addition 
of  lead  acetate  will  give  a  precipitate  of  Pb(Ci8H3502)2,  which 
is  not  soluble  in  ether  (difference  from  oleic  acid). 

STEARATES.    The  alkali  stearates  are  alone  soluble  in  water. 

178.  Stearates  heated  with  dilute  hydrochloric  acid  cause 
a  separation  of  stearic  acid,  which  floats  on  the  surface  as  an 
oily  liquid,  and  on  cooling  solidifies 

153.  VALERIC  ACID  AND  VALERATES  (Valerianic  Acid), 

179.  VALERIC  ACID   (HC5H902)  is  a  volatile  bad-smelling, 
colorless,  oily  liquid. 

180.  VALERATES  have  the  characteristic  odor  of  valerian, 
especially  when  warmed. 

181.  Sulfuric   Acid  added  in  slight  excess  to  a  solution  of  a 
valerate  will  decompose  the  latter,  and  an  oily  layer  of  valeric 
acid  will  rise  to  the  surface. 

154.  Detection  of  Acids  in  Insoluble  Substances. — Boil  some 
of  the  substance  in  a  flask  for  five  minutes  or  so  with  a  strong 
solution  of  Na2C03,  cool,  filter,  and  neutralize  the  filtrate  with 
HN03,  carefully  avoiding  excess  of  the  acid. 

All  the  acid  radicals  of  the  substance  will  be  converted 
into  corresponding  sodium  salts  and  dissolved  in  the  aqueous 
solution,  which  is  then  tested  for  the  acid. 


126 


QUALITATIVE  CHEMICAL  ANALYSIS. 


155.     CHART  FOR  THE  OBSERVATION  OF  REACTIONS  OF 
ACIDS  OF   "UNCLASSIFIED"   GROUP  G. 


Lactates. 

Oleates. 

Stearates. 

Valerates. 

HEAT. 

Above  160°  C. 
emits  an  inflam- 
mable vapor  and 
burns  with  a  pale 
flame. 

Chars. 

Chars. 

Chars. 

H,S04 

Evolution  of  a 
large  quantity  of 
CO. 

An     oily 
layer  of 
valeric 
acid   sep- 
arates. 

AgN03 

The  AgNO3  is  re- 
duced and  silver 
deposits  slowly. 

KMnO4 

-fH2SO4+heat  = 
evolves    odor   of 
aldehyd. 

HgN03 

Boil  with  a  strong 
solution  of  alkali 
lactate-pink  ppt. 

Pb(C2H302)2 

White  ppt. 
Soluble 
in  ether. 

+KOH  and  solu- 
tion neutralized, 
+Pb(C2H302)2  = 
white  ppt.  In- 
soluble in  ether. 

HC1 

Heated  =  s  t  e  a  r  i  c 
acid  separates 
and  solidifies  on 
cooling. 

PART  III. 
QUALITATIVE   ANALYSIS   OF   ORGANIC    SUBSTANCES. 

156.  If  a  substance  chars  when  heated  on  platinum  foil,  or 
burns  with  evolution  of  carbon  dioxid,  its  organic  nature  is 
established. 

The  Procedure  for  the  Detection  of  the  Ultimate  Constituents 
of  Organic  Substances  is  as  follows : 

(1)  Carbon  and  Hydrogen. — Mix  a  small  quantity  of  the 
substance  with  about  six  times  its  bulk  of  freshly  ignited  and 
powdered  cupric  oxid,  place  the  mixture  in  a  small  test-tube 
and  cover  it  with  a  layer  of  cupric  oxid.     Then  close  the  tube 
securely  with  a  cork  bearing  a  deli  very- tube  bent  twice  at  right 
angles,  and  apply  heat,     (a)  Gas  is  evolved  (C02).     The  gas 
is  passed  into  a  clear  solution  of  Ba(OH)2.     If  the  solution 
becomes  turbid  (through  formation  of  BaCOs),  carbon  is  indi- 
cated.    (6)  If  drops  of  water  or  moisture  are  deposited  in  the 
upper,  cold  part  of  the  tube,  hydrogen  .is  indicated. 

(2)  Nitrogen. — If  a  substance  when  heated  on  platinum, 
emits  an  odor  of  burnt  hair  or  horn,  nitrogen  is  indicated. 

The  presence  of  nitrogen  is,  however,  more  accurately 
determined  as  follows :  Mix  about  2  gm.  of  the  substance  with  4 
gm.  of  dried  powdered  soda-lime,  and  heat.  If  nitrogen  is 
present,  there  will  be  observed  an  odor  of  NH3,  recognized 
also  by  its  turning  red  litmus  blue,  and  by  its  forming  white 
fumes  when  a  glass  rod  moistened  with  HC1  is  brought  near 
the  mouth  of  the  tube. 

(3)  Chlorin. — The  presence  of  the  halogens  in  most  organi" 

127 


123  QUALITATIVE  CHEMICAL  ANALYSIS. 

compounds  cannot  be  detected  by  the  simple  addition  of 
silver  nitrate;  therefore  a  method  similar  to  the  following 
must  be  employed: 

Mix  1  gm.  of  the  substance  with  2  gm.  of  pure  CaO  in  a 
test-tube  and  heat  to  redness.  Then  dissolve  the  residue  in 
distilled  water  strongly  acidulated  with  HN03,  filter,  and  test 
for  chlorin  with  AgN03.  In  this  process  the  CaO  is  converted 
into  CaCl2. 

(4)  Sulfur. — (In  Solids.)     Mix  1  gm.  of  the  substance  with 
1  gm.  each  of  KN03  and  KOH  and  subject  the  mixture  to 
fusion.     The  sulfur  is   oxidized,   and  converted  into   K2S04. 
The  fused  mass  is  then  dissolved  in  distilled  water,  acidified 
with  HC1,  and  tested  with  BaCl2.     A  white  ppt.  (BaS04)  indi- 
cates sulfur. 

(In  Liquids.)  Sulfur  is  detected  by  heating  3  cc.  of  the 
liquid  with  strong  HN03.  This  converts  the  sulfur  into  H2S04, 
which,  after  diluting  with  water,  is  tested  with  BaCl2. 

(5)  Phosphorus  may  be  detected  as  described  above  (for 
sulfur  in  solids).    The  fusion  converts  phosphorus  into  H3P04. 
The  fused  mass  is  dissolved  in  water  and  tested  for  phosphate 
with  magnesia  mixture. 

Another  way  is  to  heat  about  2  gm.  of  the  substance  with 
HN03,  dilute  with  water,  filter,  and  test  separate  portions 
of  the  filtrate  with,  first,  FeCl3  in  presence  of  sodium  acetate 
=  a  brown  ppt. ;  and,  second,  ammonium  molybdate  solution  = 
a  yellow  ppt. 

157.  BEHAVIOR  OF  ORGANIC    SUBSTANCES  WITH 
IMMISCIBLE  SOLVENTS. 

Upon  agitating  the  substance  with  distilled  water  acidulated 

with  2%  of  //2$04,  and  adding  half  its  volume  of  an  immiscible 

solvent  (ether,  chloroform,  or  benzene)  the  following  are  extracted: 

(1)  In  the  Acidulated  Aqueous  Liquid  there  may  be  dissolved 

carbohydrates,  soluble  alkaloidal  salts,  acids,  organic  bases,  and 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    129 

proteids.  Add  a  small  excess  of  NaOH  solution  and  half  its 
volume  of  an  immiscible  solvent  and  again  shake,  thus  further 
separating  the  above  into  (a)  and  (b). 

(a)  The  Alkaline  Aqueous  extract  may  contain: 
Carbohydrates;   as,  dextrin,  sugars,  gums. 
Soluble  Alcohols;   as,  methyl,  ethyl,  propenyl. 
Soluble  Acids ;  as,   acetic,   tartaric,  citric,  lactic,  malic, 

oxalic. 
Alkaloids  and  Organic  )  as,  urea,  curarine,    cinchonine, 

Bases;  )      pyridine,  and  morphine. 

Coloring  matters;  as,  indigo,  cochineal,  cudbear. 
Proteids;  as,  albumin,  casein,  gelatin. 

(b)  The  Immiscible  layer  may  contain: 

Vegetable  Alkaloids;  as,  quinine,  strychnine,  aconitine, 

atropine,  nicotine. 
Coal-tar  Bases;    as,   aniline,   chrysotoluidine,   pyridine, 

and  their  homologues. 

(2)  In  the  Immiscible  Solvent  there  may  be  dissolved  hydro- 
carbons, oils,  acids,  coloring  matters,  resins,  phenols,  and  glucos  ids. 
Add  water  containing  a  small  excess  of  NaOH  and  shake  again, 
thus  further  separating  the  above  into  (a)  and  (b). 

(a)  The  Alkaline  Aqueous  Extract  may  contain: 
Fatty  acids;  as,  stearic,  oleic,  palmitic,  valeric. 
Aromatic  acids;  as,  benzoic,  salicylic,  phthalic. 

}  as,  picric  or  chrysophanic  acid; 
Acid  coloring  matters  I  saffranin,   alizarin,    or 

j       bilirubin. 

Acid  Resins;  as,  colophony  (common  pitches). 
Phenols;  as,   phenic  and  cresylic    acids;    thymol    and 

creosote. 
Glucosids;  as,  santonin,  picro toxin. 

(b)  The  Immiscible  layer  may  contain: 
Hydrocarbons,   solid;    as,    paraffin,    naphthalene,    an- 
thracene. 


130 


QUALITATIVE  CHEMICAL  ANALYSIS. 


Hydrocarbons,  liquid;  as,  petroleum  products,  rosin- 
oil,  benzene. 

Essential  oils;  as,  turpentine,  terpene,  and  oxygenated 
oils. 

Nitro-compounds ;  as,  nitro-benzene. 

Chloroform,  also  Ethers ;  as,  ethyl  oxid,  ethyl  acetate,  etc. ; 
nitro-glycerin. 

Fixed  fats,  oils,  and  waxes. 

Neutral  resins  and  coloring  matters. 

Camphors;  as,  laurel-camphor,  borneol,  menthol. 

Insoluble  Alcohols ;  as,  amyl,  cetyl,  and  cholesterin. 

Glucosids;  as,  saponin,  santonin,  and  digitalin. 

Weak  Alkaloids;  as,  caffeine,  narcotine,  pipeline,  col- 
chicine. 


158.  BEHAVIOR    OF     ORGANIC     SUBSTANCES    WITH 
FEHLING'S  SOLUTION. 

The  substance  should  be  made  perfectly  neutral  and  brought 
into  solution.  One  cc.  of  the  solution  is  heated  with  10  cc. 
of  Fehling's  Reagent  to  boiling.  In  some  cases  the  reduction 
occurs  in  the  cold  or  on  gently  heating  the  liquid.  A  yellow 
or  orange-red  precipitate  or  turbidity  caused  by  the  precipita- 
tion of  cuprous  oxid  (Cu20)  indicates  reducing  substance,  thus* 


Fehling's  Reagent  is  Reduced  by 

Carbohydrates.  —  Lactose,     dextrose, 

Isevulose,  maltose,  mannitose,  ara- 

binose,  galactose. 
Alcohols      and      Phenols. — Aldehyd, 

chloral,  chloroform,  valeric  aldehyd, 

resorcinol. 
Organic  Acids. — Pyrogallic,  gallotan- 

nic,  trichloracetic. 
Inorganic  Adds. — Arsenous. 


Fehling's  Reagent  is  Not  Affected  by 

Carbohydrates. — Mannite,  saccharose, 
dulcite,  cellulose,  dextrin,  arabin. 

Alcohols  and  Phenols. — Alcohol,  gly- 
cerin, phenol,  benzoic  and  salicylic 
aldehyds. 

Organic  Acids. — Acetic,  oxalic,  suc- 
cinic,  lactic,  tartaric,  citric,  gallic, 
mucic,  benzoic,  and  salicylic. 

Inorganic  Acids. — Sulfurous,  etc. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    131 


159.  CHART    FOR   THE    DETECTION    OF   THE    MORE 

COMMON  ORGANIC  COMPOUNDS  OF 

PHARMACEUTICAL  INTEREST. 

Dissolve  a  small  quantity  of  the  dry  substance  in  a  little 
dilute  HC1,  and  add  a  drop  or  two  of  potassio-bismuthic  iodid 
solution  or  Mayer's  reagent.  If  a  reddish-brown  ppt.  forms,  an 
alkaloid  is  indicated.  Apply  Step  I.  If  no  ppt.  forms,  pass  on 
to  Step  V  and  then  to  Step  VI. 

STEP  I. — To  a  drop  of  HNOs  on  a  white  porcelain  tile  add 
a  small  quantity  of  the  substance  and  observe  the  color. 


Red  changing  to  yellow  =  Morphine. 

H2SO4  containing  in  each  mil  .005 
Gms.  of  selenous  acid,  gives  a  blue 
color,  changing  to  green  and  then 
to  brown. 

An  aqueous  solution  of  pot.  ferricy- 
anid  containing  a  drop  of  FeCl3 
T.S.  yields  a  blue  solution  and  finally 
a  blue  precipitate. 

Frohde's  Reagent  gives  a  pui  pie  color. 

Sulphuric  acid  containing  a  crystal 
of  KIO3  =  a  dark  brown. 

A  few  drops  of  FeCl3  sol.  added  to  a 
neutral  solution  (1  :  100)  of  mor- 
phine =  a  blue  color  destroyed  by 
acids,  alcohol  or  heat. 

Sulphuric  acid  containing  in  each  mil 
1  drop  of  sol.  of  formaldehyde  gives 
with  morphine  an  intense  purple 
color. 


Blood-red = Brucine. 
Color  changes  to  purple  on  addition  of 

a  drop  of  Na2S2O3  solution. 
To     crystal     of     the     alkaloid     add 

chlorin-water  =  an  evanescent  rose- 
red. 
To  another  crystal  add  HNOs,  then 

some  solution  of  AgNOs,  and  warm 

=  a  carmine  red. 
To     another     crystal     add    bromin- 

water  =  a  yellow  ppt.,  and  forming 

a  red  sol.  on  warming. 


Yellow  changing  to  Red  on  heating  = 
Physostigmine, 

With  H2SO4  Physostigmine  yields  a 
faint  yellow  color. 

With  H2SO4  containing  a  crystal  of 
KIO3  =  a  purple  color  changing  to 
yellowish  red. 

KOH  added  to  the  aqueous  sol.  yields 
a  white  ppt.  which  quickly  turns 
pink  soluble  in  excess  to  a  pink  or 
red  sol.  which  fades  to  yellowish 
green. 

Evaporate  about  .005  Gms.  of  the  salt 
to  dryness  with  a  few  drops  of 
NH4OH  =  a  blue  residue,  soluble  in 
alcohol,  and  when  thus  dissolved, 
produces  a  red  solution  on  addition 
of  an  excess  of  acetic  acid. 


Reddish  Brown  =  Aconitine. 

With  H2SO4  containing  a  crystal  of 
ammonium  vanadate  =  orange  color. 

With  H2SO4  and  a  grain  or  two  of 
sugar  =  red  color. 

With  H2SO4  on  gently  warming  = 
violet  color. 

With  Frohde's  Reagent = a  yellow- 
brown  color. 


132 


QUALITATIVE  CHEMICAL  ANALYSIS. 


Red  Crystals  with  yellow-colored  solu- 
tion =  Codeine. 

With  H2SO4  and  warming  =  a  violet 
color. 

With  H2SO4  and  a  trace  of  FeCl3  =  a 
violet-blue  color. 

With  H2SO4  containing  a  little  HNO3 
upon  heating  gives  a  blood-red  color. 

H2SO4  containing  .005  gm.  of  selenous 
acid  in  each  mil  produces  a  green 
color  changing  rapidly  to  blue,  then 
slowly  back  to  grass  green. 


Purple  fading  to  orange  =  Apomor- 
phine. 

With  H2SO4  and  a  trace  of  FeCl3  = 
a  pale  blue. 

With  H2SO4  containing  a  trace  of 
HNO3  =  a  blood-red  color. 

With  H2SO4  containing  a  little  par- 
aldehyde  =  a  green  color  fading  to 
reddish  brown. 

Dilute  FeCl3  sol.  colors  the  alkaloid 
solution  red. 

An  aqueous  solution  (1  :  100)  with  a 
solution  of  NaHCO3  =  a  white  or 
pale-greenish-white  ppt.,  rapidly 
becoming  green  and  dissolves  in 
ether  with  a  violet  color,  and  in 
chloroform  with  a  violet-blue  color. 

With  AgNO3  T.S.  it  produces  a  white 
ppt.  insoluble  in  HNO3,  the  ppt. 
turns  black  by  reduction  to  Ag,  and 
is  instantly  reduced  by  NH4OH. 


160.  STEP  II. — Cover  a  few  grains  of  the  alkaloid  with  a  drop 
or  two  of  cone.  H2S04  on  a  white  porcelain  tile,  and  add  a 
small  fragment  of  potassium  dichromate.  Observe  effect. 

Green 

color  slowly  formed  =  Caffeine  (not  an 


Deep  Blue 

quickly  changing  to  violet,  purple, 
cherry-red  and  finally  to  orange  = 
Strychnine. 

With  H2SO4  containing  1%  of  ammo- 
nium vanadate  =  a  violet-blue,  grad- 
ually changing  to  cherry-red. 

With  H2SO4  containing  a  trace  of 
KIO3  =  a  violet  color,  changing  to 
purple. 


alkaloid). 

If  .01  Gm.  of  salt  be  dissolved  in  1  mil 
of  HC1  and  .1  Gm.  KC1O3,  and  the 
sol.  evaporated  to  dryness,  the  resi- 
due, subjected  to  the  vapor  of  am- 
monia, will  acquire  a  rich  purple 
color  destroyed  by  fixed  alkalies. 

An  aqueous  solution  yields  a  ppt.  with 
tannic  acid  T.S.,  soluble  in  excess. 


Odor  of  bitter  almonds  =  Atropine. 

Heated  with  a  few  cc.  of  H2SO4  =  a 
peculiar  odor,  resembling  a  mix- 
ture of  rose,  orange  flower  and 
melilot.  The  addition  of  a  crystal 
of  K2Cr2O?  develops  an  odor  of 
bitter  almonds. 

With  AuCl3  a  yellow  lusterless  ppt. 
is  produced  in  a  dil.  HC1  solution 
of  atropine. 

Evaporate  .01  Gm.  to  dryness  with  a 
few  drops  of  HNO3  =  a  yellow-col- 
ored residue.  Cool,  add  a  few  drops 
of  alcoholic  KOH  and  a  fragment 
of  KOH  =  an  intensely  violet  color. 


Pale  Yellowish  Pink  =  Cocaine. 

If  5  drops  of  CrO3  sol.  (1  :  20)  be  added 
to  5  mils  of  cocaine  sol.  (1-50)  =a 
yellow  ppt.,  dissolved  on  shaking. 
On  now  adding  1  mil  of  HC1  an 
orange-colored  ppt.  is  produced. 

Its  solution  in  HC1  gives  with  K2CrO4 
sol.  an  orange  ppt. 

1  mil  of  cocaine  sol.  is  treated  with 
2  mils  of  N/10  V.S.  of  KMnO4.  A 
violet  ppt.  is  produced,  which  when 
examined  under  a  microscope,  is 
seen  to  consist  of  rectangular  plates. 

A  solution  added  to  2%  hexamethylen- 
amin+H2SO4  =  wine  color  on  warm- 
ing. 

If  AgNO3  T.S.  is  added  to  a  1%  solu- 
tion =  a  white  ppt.  insol.in  HNO3. 


CALIFORNIA   COLLE6F 

of  PHARMACY 

QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES. 


133 


161.  STEP  III. — To  a  fragment  of  the  alkaloid  on  a  porcelain 
crucible  cover  add  a  few  drops  of  cone.  HC1  and  warm. 

A  Rose-red  color =  Veratrine. 

Confirmatory  tests : 

Heated  with  H2S04  =  a  cherry-red  color. 

H2S04  added  to  a  mixture  of  1  part  of  veratrine  and  6  parts 
of  sugar  produces  a  green  color  which  changes  to  blue  and  finally 
becomes  colorless. 

With  HN03  =  a  dirty-red  color. 

With  Frohde's  reagent  =  a  cherry-red. 

(See  also  Physostigmine.) 

162.  STEP  IV. — Heat  a  little  of  the  original  in  a  dry  test-tube. 
Vapors  are  evolved,  first  yellow  then  red  =  cinchona   alkaloids. 
Take  1  mil  of  a  solution  of  the  alkaloid,  dissolved  in  water 
with  the  aid  of  the  least  quantity  of  dilute  ^SO-i,  add  2  or  3 
drops  of  bromin-water,  and  a  slight  excess  (1  mil)  of  ammonia- 
water.     An  Emerald  Green  Color  indicates  Quinine  or  Quinidine ; 
a  white  ppt.  may  indicate  Cinchonine   or   Cinchonidin.    Apply 
the  following  tests : 


REAGENT. 

Quinine. 

,           Quinidine. 

A  1%  solution  of  the  alka- 
loid, made  by  using  the 
smallest  possible  quantity 
of  dil.  H?SO4  and  neu- 
tralized with  NH4OH,  is 
treated  with  one  drop  of 
H2O2  and  one  drop  of 
CuSO4  sol.  and  boiled. 

Intense    red    color 
changing    to    blue 
and  green. 

Intense  red  color 
changing  to  blue 
and  green. 

Dissolve  a  small  quantity  of 
the  alkaloid  in  a  mixture 
of  acetic  acid  and  alcohol 
with  a  few  drops  of  H2SO4, 
boil,  and  add  tr.  iodin 
slowly. 

Bronze  or  olive-green 
crystals  separate  on 
cooling. 
(Quinine-iodosul- 
phate.) 

No  ppt.  or  crystals. 

To  a  neutral  aqueous  solu- 
tion add  (NH4)2C2O4  or 
KNaC4H4O,  sol. 

White  ppt. 

Precipitate  only  on 
addition  of  KI  and 
shaking. 

Frohde's  Reagent. 

Green  color. 

Green  color. 

134 


QUALITATIVE  CHEMICAL  ANALYSIS. 


REAGENT. 

Cinchonin. 

Cinchonidin. 

Make  a  nearly  neutral  solu- 
tion of  the  alkaloid.     Add 
some  .sat.   sol.  of 
KNaC4H4O6. 

No  white  ppt.  unless 
excess  of  NH4OH  is 
added. 

A  white  ppt. 

Make  a  solution  of  the 
alkaloid  in  HC2H3O,.  Add 
some  NH4OH,  and  then 
an  excess  of  ether. 

The  ppt.  does  not 
dissolve  in  the  ether. 

The  ppt.  dissolves  in 
the  ether. 

163.  STEP  V. — If  the  substance  is  not  an  alkaloid,  place  a 
small  portion  of  it  on  a  porcelain  crucible  cover,  add  a  drop  or  two 
of  Frohde's  Reagent  and  observe  the  color  changes. 


Salicin. 


Santonin. 


Intense  violet  color  changing  to 
reddish  brown. 

With  H2SO4  =  a  bright-red  color  which 
disappears  on  the  addition  of  water. 

To  .1  Gm.  of  the  substance  add  2  mils 
of  dilute  sulfuric  acid  and  .2  Gm.  of 
K2Cr2O7  and  boil  =  odor  of  sweet 
clover  (salicylic  aldehyd). 

On  heating  a  portion  of  the  sub- 
stance in  a  test-tube  until  it  turns 
brown,  then  adding  a  few  mils  of 
water  and  a  drop  of  FeCla  sol.  =a 
violet  color. 


Slate-blue  color  on  warming. 

Add   a   drop   of   FeCls   to    1    mil   of 

H2SO4,  warm,  and  add  .01  Gm.  of 

the   substance  =  a    violet-red    color 

changing  to  brown. 
On  heating  .5  Gm.  of  the  substance 

with  5  mils  of  alcoholic  KOH  sol. 

=  a  red  color. 
The  substance  is  soluble  in  NaOH, 

reprecipitated  by  acids. 


Elaterin. 


Aloin. 


Faint  red  changing  to  olive-green  on 
warming. 

Add  5  mils  of  phenol,  then  a  few  drops 
of  H2SO4,  to  .01  Gm.  of  the  sub- 
stance and  warm  =  a  crimson  chang- 
ing to  a  scarlet  color. 

With  H2SO4  =  a  yellow  color  changing 
to  red. 

.01  Gm.  with  1  mil  H2SO4+a  drop  of 
formaldehyde  =  a  brown  color. 

With  H2SO4+a  trace  of  ammonium 
vanadate  =  a  blue,  changing  to 
green  and  brown. 


Yellow  color  changing  to  green. 

Ammonia- water  and  alkali  sols,  dis- 
solve aloin  forming  a  yellow  sol. 
quickly  turning  red  and  exhibiting 
a  green  fluorescence. 

With  cone.  H2SO4+a  crystal  of  K2Cr2O7 
=  an  olive  green,  and  finally,  on 
standing,  a  blue  color. 

With  bromine-water  =  a  pink  color. 

With  AuCl3  in  an  aqueous  solution  = 

a  carmine-red  changing  to  violet. 
With  a  drop  of  FeCls  sol.  its  alcoholic 

sol.  gives  a  brownish-green  color. 
HNp3  gives  with  barbaloin  a  crimson, 

with    nataloin    a    red,    and    with 

soraloin  a  brown,  ppt. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    135 


164.  STEP  VI.  —  Heat  some  of  the  substance  in  a  dry  test-tube 
and  observe  odor  or  other  effect. 
(a)  Odor  of  Phenol  indicates: 

Phenol  (see  paragraph  139). 

Phenolates  (see  paragraph  139). 

Phenolsulfonates  (see  paragraph  138). 
(6)    Odor  is  Pungent;   may  be  Chloral,  Benzoic  Acid,  Ben- 

zoates,  or  Butyl  Chloral. 


Cblor  1. 


'  c'd 


B  n^ 


Bityl  Cbl^rel. 


Heated  with  KOH  or 
NH<OH  an  odor  of 
ch.oioform  is  evolved 
and  a  formate  of  the  base 
is  produced. 

Warmed  with  a  few  drops, 
of  aniline  and  some 
KOH  =  a  very  disagree- 
able odor  of  phenyl- 
isocyanide. 

Warmed  with  a  few  drop ; 
of  NH4OH  and  a  little 
AgNO3  sol .  =  a  silver  mir- 
ror. 

Boiled  with  Fehling's  sol. 
=  a  red  ppt. 


Upon  heating  benzoic  acid 
with  freshiy  siaked  lime 
in  a  dry  test-tube  ben- 
zene (benzol)  is  evolved. 

A  sol.  of  benzoic  acid  in 
NaOH  neutralized  care- 
fully gives  with  neutral 
ferric  chloride  sol.  a  pale 
buff  or  flesh-colored  ppt. 

See  par.  135  for  j tests  for 
benzoates. 


Sparingly  soluble  in 
water.  Boil  with 
NaOH,  neutralize 
with  dilute 
HC2H3O2  and  add 
AgNO3  sol.  =  a 
white  ppt. 


(c)   Odor  is  Pungent;  with  lodin  Fumes  indicates lodoform, 
lodol,  or  Aristol. 


Iolcf}rm. 

lodol. 

Aristol. 

A  yellow  insol.  powder. 
When  boiled  with 
NaOH  and  the  so', 
neutralized  with 
HNO3  =  a  ye!  ow  ppt. 
on  adding  AgNO,  sol., 
and  a  blue  rolor  on 
adding  starch  sol. 

A    grayish-brown    pow- 
der     very     sparingly 
soluble  in  water. 
When  dissolved  in  cone. 
H2SO4    a    green    sol. 
results  gradually 
changing  to  brown. 

A  bright  chocolntc-colored 
powder,  with  an  aro- 
matic odor. 
It  is  not  sol.  in  alkaline 
hydroxid  solutions. 
Heated  with  cone.  H2SOL 
it      decomposes,      ana 
iodine  separates. 

136 


QUALITATIVE  CHEMICAL  ANALYSIS. 


(d)  Odor  is  Camphoraceous;  may  be  Camphor,  Thymol,  or 
Menthol. 


Camphor. 

Thymol. 

Menthol. 

Soluble    in    the   volatile 

An     aromatic     thyme- 

Soluble  in  alcohol,  chlo- 

solvents,  and  in   fixed 

like  odor. 

roform   and   ether.     It 

oils. 

.Soluble  in  ether,   chlo- 

has  a   peppermint-like 

Its     alcoholic     solution 

roform,    alcohol,    and 

odor. 

poured  into  cold  water 

oils,     also    in    glacial 

It  is  soluble  in  glacial 

=  a  curdy  white  ppt. 

acetic  acid. 

acetic    acid,    but    does 

When    triturated     with 

Its    sol.    in    the    latter 

not  respond  to  the  test 

hydrated  chloral  lique- 
faction ensues. 

when      treated      with 
6  drops  of  H2SO4  and 

for  thymol. 
Heated  with  diluted  sul- 

It    is   inflammable    and 

a  drop  of  HNO3  exhib- 

furic acid  1  :  2  =  a  deep- 

burns    with     a     lumi- 

its a  bluish-green  color 

blue  color. 

nous  smoky  flame. 

by  reflected  light. 

If  1  Gm.  is  heated  with 

5  mils  of  a  10%  solution 

of  NaOH  in  a  test-tube 

a  pale-red  sol.  is 

formed  which  becomes 

darker      on     standing 

without  the  separation 

of  oily  drops.     A  few 

drops    of     chloroform 

added   gives   a   violet 

color. 

(e)   Odor  is  Acrylic  (Fatty  Acid);  indicates   Soap,  Oleates, 

or  Stearales. 

Soap. — Dissolve  in  water,  add  HC1  and  shake,  add 
some  ether  and  again  shake;  then  let  the  mixture 
stand  so  that  the  ethereal  layer  can  separate;  remove 
the  upper  layer  and  evaporate:  the  residue  if  liquid 
is  oleic,  and  if  solid,  stearic  acid.  The  HC1  sol.  is 
evaporated  to  dry  ness  and  tested  for  K  and  for  Na. 
Oleates  and  Stearates  of  the  heavy  metals  are  treated 
in  the  same  way.  The  acid  sol.  residue  being  tested 
for  the  metals  commonly  combined  with  these  fatty 
acids,  i.e.,  Zn,  Pb,  Hg,  etc. 

(/)   Odor  resembling  Burnt  Bones ;  may  indicate  Oxgall. 
To  a  warm  solution  of  oxgall,  2  drops  in  10  mils  of  H20 
add  ft  crystal  of  sugar;    shake,  and  add  H2S04  cau- 
tiouslv  until  the  ppt.'  first  formed  is  redissolved;    a 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    137 


brownish-red    color  gradually  develops,  changing  to 
carmine,  purple,  and  violet. 

(g)  Odor  of  Burning  Sugar;  may  be  Sugars,  Dextrin, 
Starches,  Gums,  Tartaric  Acid  or  Tartrates.  Apply 
special  tests.  For  tartirates,  see  paragraph  146.  For 
the  sugars,  see  the  Table  below. 


Cane-sugar. 


Milk-sugar. 


Strong  H2SO4  chars  it  immediately. 

Does  not  reduce  Fehling's  sol. 

Mixed  dry  with  KC1O3  crystals  and  a 
drop  of  cone.  H2SO4  added,  it  defla- 
grates. 

It  does  not  ferment  with  yeast  until 
left  in  contact  for  some  time. 

Boiled  with  NaOH  =  no  effect. 

It  does  not  form  a  compound  with 
phenylhydrazine. 


Strong  H2SO4  chars  it  slowly. 

It  reduces  Fehling's  sol. 

It  does  not  ferment  with  yeast. 

It  combines  with  phenylhydrazine  to 

form   phenyl-lactosazcne   in  acetic 

acid  solutions. 
Boiled  with    NaOH  solution  becomes 

yellow,  then  brown. 


Gr  p  -sug  r. 


D  x.rln. 


Strong  H2SO4  does  not  char  it  until 
heated. 

It  readily  reduces  Fehling's  sol.  It 
also  reduces  alkaline  solutions  of 
Bi,  Ag,  and  Hg. 

In  a  solution  acidified  by  HC2H3O2 
it  forms,  with  excess  of  phenyl- 
hydrazine, a  yellow  ppt.  of  phenyl- 
dextrosazone. 

It  ferments  readily  upon  adding 
yeast  to  its  solution. 

Boiled  with  NaOH  =  a  deep-brown 
color. 


Strong  H,SO4  =  no  effect. 

In  aqueo  is  sol.  reduces  Fehling's  sol. 

only  after  long  boiling. 
Boiled  with  NaOH  =  no  effect. 


Starches.     Insoluble    in  cold  water,  but  on  boiling  it 

forms  a  mucilage,  which  gives  a  blue  color  with  iodin. 
Boiled  with  dilute  sulfuric  acid,  it  is  converted  into 

dextrose,  and  then  reduces  Fehling's  sol. 
Gums.     Soluble  in  cold  water,   from  which  sol.  it  is 

precipitated  by  alcohol,  borax  or  lead-acetate  solution. 
Gum  arabic  is  an  arabate  of  calcium.     Ignite  some  of 

it,  dissolve  the  ash  in  dilute  acetic  acid  and  test  for 

Ca,  with  (NH4)2C204. 


138  QUALITATIVE  CHEMICAL  ANALYSIS. 

(h)  If  detonation  occurs,  it  indicates  Picric  Acid.  Dissolve  a 
little  of  the  substance  in  NaOH  sol.,  add  a  little  sugar, 
and  warm  the  mixture = a  blood-red  color. 

To  an  aqueous  solution  add  a  solution  of  gelatin = a 
white  ppt. 

Its  aqueous  solution  precipitates  albumin,  and  gives  a 

green  ppt.  with  ammonio- copper  sulfate. 
(i)  If  it  burns  with  a  smoky  flame,  it  may  be  resin. 

Resin.  Insoluble  colored  substance.  A  small  piece  of 
it  treated  with  strong  H2S04  gives  a  red  coloration; 
add  a  drop  of  H20  to  this  =  balsamic,  turpentiny  odor. 

Guaiacum  Resin.  Insoluble  colored  substance.  Dis- 
solved in  alcohol  and  treated  with  FeCl3  gives  a 
blue  coloration.  A  small  piece  of  it  treated  with 
strong  H2S04  for  a  few  seconds,  then  water  added, 
gives  a  characteristic  balsamic  odor. 

0)  If  at  first  it  melts  and  then  upon  highly  heating  burns 
away  entirely,  it  may  be  acetanilide,  antipyrine,  phen- 
acetin,  saccharin,  naphthalene,  or  urethane. 

Acetanilide;  .1  Gm.  of  acetanilide  heated  with  5  mils  of 
concentrated  solution  of  KOH,  and  1  mil  of  chloroform 
added  =  a  disagreeable  odor  of  phenyl  isocyanide 
(distinction  from  antipyrine  and  exalgine). 

0.1  Gm.  boiled  with  2  mils  HC1  and  3  mils  of  phenol  solu- 
tion (1  :  20)  and  then  mixed  with  5  mils  of  a  clear  solu- 
tion of  chlorinated  lime  =  a  brownish-red  color,  becom- 
ing blue  upon  supersaturating  with  NH4OH. 

1  Gm.  heated  with  10  mils  of  water,  the  solution  cooled 
and  filtered  and  treated  with  bromin-water  drop  by 
drop  gives  a  whitish  ppt.  of  parabromoacetanilide. 

Antipyrine,  Phenazonum,  Phenyldimethylisopyrazolon. — 
If  .1  Gm.  of  NaN02  and  12  mils  of  1%  solution  of  anti- 
pyrine be  mixed  and  1  mil  of  dil.  H2S04  added,  a 
deep-green  color  (iso-nitrosoantipyrine)  develops. 

2  mils  of  a  solution  of  antipyrine  (1  : 1000)  treated  with  1 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    139 

drop  of  FeCl3  solution = a  deep-red  color,  which  is 
turned  yellow  by  H2S04. 

Tannic  acid  solution  gives  a  white  ppt.  HN03  produces 
a  red  coloration. 

Phenacetin,  Acetphenetidin. — A  mixture  of  .005  Gm.  with 
1  mil  of  HNOs  produces  a  yellow  color  which  persists 
on  heating  and  becomes  darker  on  standing. 

Boil  .1  Gm.  with  1  mil  of  concentrated  HC1  for  1  minute, 
the  solution  diluted  with  10  mils  of  water,  cooled  and 
filtered,  and  then  1  drop  of  K2Cr207  T.S.  added,  a 
ruby-red  color  is  produced.  FeCl3  solution  produces  a 
yellow  solution,  which  becomes  blood-red  on  boiling. 

Boil  .1  Gm.  with  10  mils  of  water,  cool,  filter,  and  add 
bromin  water,  drop  by  drop,  until  solution  remains 
permanently  yellow,  no  ppt.  is  produced. 

A  mixture  of  .3  Gms.  with  1  mil  of  alcohol  and  1  drop  of 

N 

JQ  I.  V.  S.  does  not  acquire  a  red  tint  when  diluted 

with  3  times  its  volume  of  H20  and  boiled. 

Saccharin — Glusidum,  Benzosulfinid. — It  has  an  intensely 
sweet  taste.  It  is  soluble  in  alkali  solutions  and  in 
NaHC03  solution  with  evolution  of  C02.  If  subjected 
to  a  high  temperature,  it  melts  and  finally  burns, 
giving  off  an  odor  of  essential  oil  of  bitter  almonds. 

Heated  to  redness  with  Na2C03,  it  chars  and  gives  off  an 
odor  of  benzene. 

Its  solution  in  NaHC03,  neutralized  with  HC1,  gives  with 
FeCl3  a  reddish-brown  color. 

Fuse  with  5  times  its  weight  of  NaOH  =  NH3  is  evolved. 
Continue  to  heat,  dilute  with  10  mils  of  H20,  neutralize 
with  dilute  HC1,  add  1  drop  of  FeCl3  T.S.  =  violet  color. 

Naphthalene.  —  It  melts  and  volatilizes;  its  vapor  is 
inflammable,  burning  with  a  luminous  smoky  flame. 

It  may  be  recognized  by  its  characteristic  odor,  resem- 
bling that  of  coal-tar. 


CALIFORNIA   COLLEGF 

of   PHARMACY 


140  QUALITATIVE  CHEMICAL  ANALYSIS. 

It  is  insoluble  in  H20  but  soluble  in  the  volatile  solvents. 
Urethane,    Ethyl  Carbamate.  —  When   heated   it   melts, 

when  highly  heated  it  is  decomposed,  burning  without 

leaving  a  residue. 
1  Gm.  added  to  5  mils  of  H^SC^  and  gently  heated  is 

decomposed,  with  evolution  of  CCb,  while  alcohol  and 

NH4HS04  remain  in  solution. 
When  1  Gm  is  heated  with  5  mils  of  concentrated  solution 

of  KOH,  ammonia  is  given  off . 
If  .5  Gm.  be  dissolved  in  5  mils  of  water,  together  with  1 

mil  of  Na2COs  and  about  .01  Gm.  of  iodin  and  warmed, 

yellow  crystals  of  iodoform  are  produced. 
(&)  If  at  first  it  melts  and  at  red  heat  is  decomposed  without 

burning  it  may  be  (1),  if  without  odor,  Chloralforma- 

mide;  (2)  if  with  odor  of  SCb,  Sulfonal  or  TrionaL 
Chloralformamide,  Chloralamide. — It  is  soluble  in  water. 
It  is  not  affected  by  dilute  acids. 
Its  solution  is  decomposed  when  warmed  with  KOH;  it 

becomes  turbid,  then  clear,  and  gives  off  chloroform. 
Sulfonal,    Sulfomethane,    Diethylsulfondimethylmethane.— 

Slightly  soluble  in  cold,  readily  in  hot  water.    When 

heated  it  melts.    At  a  red  heat  it  is  consumed  and 

S02  is  evolved. 
When  .1  Gm.  is  heated  with  an  equal  weight  of  powdered 

charcoal,  in  a  dry  test-tube,  the  disagreeable  odor  of 

mercaptan  is  developed. 
When   heated   with   dry   NaC2H302,    gaseous   H2S   is 

evolved. 
Trional,    Sulfonethylmethane. — The  tests  for  trional  are 

the  same  as  those  described  for  sulfonal. 
It  differs  in  solubility,  being  soluble  in  195  parts  of  water 

at  77°  F.  while  sulfonal  requires  360  parts  of  water. 

It  is  also  more  soluble  in  ether  and  in  alcohol  than 

sulfonal.    Trional    has    a    bitter    taste;     sulfonal    is 

tasteless. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    141 

(0  If  at  first  it  melts  and  finally  upon  increasing  the  heat 
volatilizes  or  sublimes,  it  may  be  Resorcinol,  Cam- 
phor Monobromated,  Guaiacol  Carbonate;  and  if  it 
has  a  phenol-like  odor,  Betanaphthol,  or  if  an  aro- 
matic odor,  Salol,  Guaiacol,  or  Terpin  Hydrate. 

Resorcinol,  Resorcin. — It  is  very  soluble  in  water,  alcohol, 
ether  and  glycerin,  slightly  soluble  in  chloroform  and  in 
CS2. 

10  mils  of  an  aqueous  solution  (1  : 200)  treated  with  a 
few  drops  of  Feds  solution  =  a  bluish  color,  changing 
to  brownish- yellow  on  adding  NH4OH. 

.1  Gm.  heated  with  1  mil  of  KOH  solution  and  a  drop  of 
chloroform  gives  a  bright  red  color  (due  to  formation 
of  rosolic  acid).  The  addition  to  this  of  a  slight 
excess  of  HC1  changes  the  color  to  pale  yellow. 

On  heating  a  fragment  with  a  grain  of  tartaric  acid, 
and  10  drops  of  H2S04,  a  thick,  red  liquid  results,  which 
becomes  pale  yellow  when  diluted  with  water. 

Camphor  Monobromated.  —  Almost  insoluble  in  water, 
freely  soluble  in  volatile  solvents  and  in  cold  concen- 
trated H2S04. 

When  heated  it  melts  and  sublimes. 

Heat  .1  Gm.  each  of  camphor  monobromate  and  AgN03 
with  2  mils  of  HN03  and  2  mils  of  H2S04  until  nitrous 
vapors  are  no  longer  given  off=a  yellow  ppt.  of  silver 
bromide. 

If  a  few  crystals  are  fused  in  a  dry  test-tube  with  metallic 
Na,  the  residue  dissolved  in  water  and  acidulated 
with  HNOs  gives  with  AgN03  solution  a  copious  white 
ppt. 

It  has  a  camphoraceous  odor  and  taste. 

Guaiacol  Carbonate. — A  white,  odorless,  tasteless  powder, 
insoluble  in  water,  very  soluble  in  chloroform,  less 
soluble  in  alcohol,  and  in  ether.  It  fuses  at  87°  C. 

It  is  decomposed  when  treated  with  an  alcoholic  KOH 


142  QUALITATIVE  CHEMICAL  ANALYSIS. 

solution,  and  from  the  solution  so  obtained  guaiacol 
may  be  separated  on  the  addition  of  an  acid,  and  iden- 
tified by  appropriate  tests. 

Betanaphthol,  Naphthol  U.  S.  P.  1890.— A  crystalline  or 
pale  buff-colored  or  colorless  powder,  having  a  faint 
phenoUike  odor.  Very  sparingly  soluble  in  water,  very 
soluble  in  volatile  solvents  and  in  alkali-hydroxid  solu- 
tions. A  cold  saturated  solution  mixed  with  NIUOH  = 
a  faint  bluish  fluorescence. 

.1  Gm.  of  betanaphthol  in  5  mils  of  KOH  solution  (1  :  4) 
treated  with  1  mil  of  chloroform  and  heated,  gives  a 
blue  color  changing  to  green  and  then  to  brown.  An 
aqueous  solution  treated  with  FeCl3  gives  a  greenish 
color,  and  after  some  time  white  flakes  separate  which 
turn  brown  when  heated. 

Salol,  Phenyl  Salicylate. — A  white,  crystalline  powder, 
having  a  faint  aromatic  odor.  Insoluble  in  water, 
very  soluble  in  the  volatile  solvents. 

With  Fed-  a  violet  color  is  produced. 

If  .2  or  .3  Gm.  of  salol  be  dissolved  in  2  mils  of  warm  NaOH 
solution  and  the  resulting  solution  acidified  with  HC1,  a 
ppt.  of  salicylic  acid  forms,  and  the  odor  of  phenol  is 
recognizable. 

Guaiacol. — A  colorless  crystalline  solid  or  a  colorless 
refractive  liquid  having  an  agreeable  aromatic  odor. 
Soluble  in  53  parts  of  water,  and  in  alcohol  and  ether  in 
all  proportions,  and  in  acetic  acid. 

The  addition  of  FeCl3  to  10  mils  of  an  alcoholic  solution 
of  guaiacol  (1  : 100)  =  an  immediate  blue  color  changing 
to  emerald  green  and  then  to  yellow  or  brown. 

Terpin  Hydrate. — (a)  It  melts  when  quickly  heated,  and 
sublimes  in  fine  needles.  When  strongly  heated  on 
platinum  it  burns  with  a  bright  smoky  flame  leaving 
no  residue. 

(&)  If  to  its  hot  aqueous  solution  a  few  drops  of  H2S04  be 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    143 

added,  the  liquid  will  become  turbid  and  develop  a 
strongly  aromatic  odor. 

165.  STEP  VII.  —  If  the  substance  is  a  liquid,  possessing  a 
characteristic  odor,  limpidity  or  viscosity,  place  about  1  mil  in  a 
test-tube  and  apply  gentle  heat  (water-bath).  If  it  is  com- 
pletely volatilized,  look  for  it  under  A.  If  it  is  not  completely 
volatilized  by  gentle  heat  look  for  it  under  B. 

1  66.  STEP  VIII.  —  If  the  substance  comes  into  Class  A,  place 
1  mil  of  it  into  a  test-tube  and  add  10  mils  of  water,  and  note 
if  it  is  miscible  or  not. 

(a)  If  it  is  miscible,  it  may  be  Acetaldehyd,  Acetic  Ether, 
Ether,  Paraldehyd,  Formaldehyd,  Ethyl  Akohol,  Methyl 
Akohol. 

(6)  If  it  is  not  miscible  or  soluble  in  10  parts  of  water 
or  more,  it  may  be  Chloroform,  Benzin,  Benzene, 
Cinnaldehyd,  Amyl  Alcohol,  Amyl  Nitrite,  Benzaldehyd. 

167.  CLASS  A.    DIVISION  a.    LIQUIDS  MISCIBLE  WITH  WATER. 

Ethyl  Alcohol,  Grain  Alcohol.  —  A  colorless,  mobile,  volatile  and 
inflammable  liquid.  Miscible  with  water  in  all  proportions. 

The  Oxidation  Test.  To  the  alcohol  add  some  K2Cr207  and 
a  small  quantity  of  H2S04,  and  heat  =  a  greenish  color  and 
an  odor  of  aldehyd. 

3C2H5OH  +  K2Cr207  +  4H2S04 

=  K2S04  +  Cr2  (S04)  3  +  3C2H3OH  +  7H20. 

Aldehyde. 

The  Acetic  Ether  Test.  To  a  small  portion  of  the  alcohol  add 
some  KC2H302  and  a  little  H2S04  and  warm  the  mixture  = 
an  odor  of  apples  due  to  formation  of  acetic  ether. 

KC2H302  +  C2H5OH  +  H2S04  -  KHS04  +  C2H5C2H302  +  H20 

Acetic  Ether. 


144  QUALITATIVE  CHEMICAL  ANALYSIS. 

The  lodoform  Test  (Leiben).  Warm  a  small  quantity  of  the 
alcohol  with  KOH  and  add  some  solution  of  iodin  =  a 
yellow  ppt.  of  iodoform,  forming  slowly.  Detects  1:2000. 

C2H5OH + 18  +  6KOH  =  CHI3  +  KCOOH + SKI  +  5H20 

lodoform.  Potass  formate. 

The  Molybdic  Test.  A 10%  solution  of  molybdic  acid  in  strong 
H2S04  warmed  with  the  alcoholic  liquid  =  a  blue  color. 
Detects  1 : 1000. 

Methyl  Alcohol,  Carbinol,  Wood  Alcohol. — A  colorless  volatile,* 
inflammable  liquid  having  a  characteristic  odor,  and  mis- 
cible  with  water  in  all  proportions.  It  forms  with  dry 
CaCU  a  crystalline  compound. 

The  Salicylate  Test.  To  a  concentrated  solution  of  sodium 
salicylate  add  some  methyl  alcohol  and  a  few  drops  of 
H2S04,  and  warm  the  mixture  =  an  odor  of  oil  of  winter- 
green  (methyl  salicylate)  develops: 

HC7H503  +  CH3OH = CH3C7H503  +  H20. 


Methyl  Salicylate. 

Methods  for  the  Detection  of  Methyl  Alcohol  in  Grain  Alcohol, 
Pharmaceutical  Preparations,  Beverages,  etc. 

The  Resorcinol  Test.  A  spiral  of  copper  wire  is  heated  to 
redness  and  plunged  into  the  liquid  (which  should  not  be 
stronger  than  10%).  One  drop  of  a  0.5%  aqueous  resorcinol 
solution  is  added  and  the  mixture  floated  on  concentrated 
H^SO*  A  rose-red  zone  at  line  of  contact  =  methyl  alcohol; 
above  the  zone  a  scanty  white  or  pinkish-white  coagulum 
appears  which  finally  separates  and  rises  in  purplish  flakes. 

Similar  reactions  are  given  with  tertiary-butyl  alcohols,  dimethyl- 
ethylcarbinol  and  formic  acid,  but  the  succession  of  colors  and 
the  deportment  of  the  flaky  coloring  matter  are  different.  If 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    145 

the  methyl-alcohol  solution  is  very  dilute,  repeat  the  immer- 
sion of  the  copper-wire  coil  several  times.  If  the  solution  is 
concentrated,  it  should  be  diluted  so  as  to  be  about  10%  by 
volume.  (Mulliken  and  Scudder,  Am.  Ch.  J.,  Vol.  XXL,  226.) 

The  Phloroglucin  Test.  The  oxidation  of  methyl  alcohol  is 
the  same  as  in  the  foregoing;  acetaldehyd  is  removed  by 
adding  to  the  liquid  remaining  in  the  test-tube  6  mils  of  a 
3%  H202  solution  and  filtering  into  a  porcelain  dish.  After 
3  minutes  add  2  mils  of  a  10%  solution  of  Na2S203,  and  then 
3  mils  of  a  phloroglucin  solution  made  by  dissolving  1  Gm. 
of  phloroglucin  and  20  Gms.  of  NaOH  in  water  to  make  100 
mils  =  a  bright  red  color  develops  if  methyl  alcohol  is  present, 
the  intensity  of  the  color  being  in  some  degree  proportionate 
to  the  quantity  of  methyl  alcohol  present.  Authority  same 
as  preceding  test. 

Prescott's  Modification  of  the  Foregoing  Tests  (see  A.  J.  of  Ph., 
Vol.  77,  108,  Sadtler).  The  spirit  tested  should  be  diluted 
to  about  10%.  The  copper  wire  is  plunged  into  the  liquid, 
held  there  for  a  second  or  two,  then  withdrawn  and  dipped 
into  water  to  cool.  This  is  repeated  5  or  6  times,  the  test- 
tube  being  immersed  in  cold  water  to  keep  contents  cool. 
The  liquid  is  then  filtered  into  a  wide  test-tube  and  gently 
boiled  to  drive  off  acetaldehyd.  The  boiling  should  be 
continued  until  no  odor  of  acetaldehyd  is  perceptible. 
Then  the  liquid  is  poured  into  a  white  porcelain  dish  and 
1  mil  of  the  phloroglucin-alkali  solution  described  in  previous 
test  added.  A  deep-red  persisting  color  =  methyl  alcohol 
(formaldehyd  reaction);  a  pale  or  slightly  yellowish-red 
fading  rapidly  is  due  to  acetaldehyd  and  indicates  only 
ethyl  alcohol. 

The  Rimini  Test,  Modified  (Haigh,  Ph.  Rev.,  Oct.,  1903). 
The  oxidation  of  the  methyl  alcohol  and  the  removal  of 
acetaldehyd  by  boiling  is  effected  as  in  foregoing  tests. 


146  QUALITATIVE  CHEMICAL  ANALYSIS. 

Then  1  mil  of  a  dilute  solution  of  phenylhydrazine  hydrochlo- 
rid  is  added,  followed  by  a  few  drops  of  a  fresh  solution  of 
sodium  nitroprusside  and  finally  by  1  mil  of  50%  solution  of 
NaOH;  if  formaldehyd  is  present  a  light-blue  or  green  color 
results,  depending  upon  the  amount  of  CH3OH  present.  If 
the  latter  is  absent,  the  color  is  greenish  yellow. 

The  U.  S.  P.  Test  (9th  Decennial  Revision).— Transfer  5  mils  of 
the  dilute  alcohol  (10%)  to  a  test-tube.  Add  to  it  2  mils  of 
a  KMn04  solution  (3  Gms.  of  KMn04  in  100  mils  of  distilled 
water)  and  .3  mil  of  H2S04  and  allow  to  stand  for  five 
minutes.  Dissolve  the  ppt.  of  Mn02  by  H2SOs,  drop  by 
drop,  then  add  1  mil  H2S04  and  5  mils  fuchsin-sulfurous 
acid  T.S.,  and  mix  them.  After  standing  for  10  minutes,  a 
colorless  liquid  results.  Indicates  absence  of  methyl  alcohol. 
If  methyl  alcohol  is  present,  the  color  of  the  fuchsin  is 
restored  and  the  solution  becomes  pink  or  red. 

Miller's  Test.  (Oxidation  with  Dichromate)  P.  J.  Tr.,  2d  Ser. 
VII,  318.  Take  J  ounce  of  the  spirit,  distil  off  about  1  dram. 
Then  place  in  a  small  distilling-flask  30  grains  of  K2Cr207, 
4  fl.  drams  of  water,  and  30  minims  of  concentrated  H2S04. 
To  this  add  30  to  40  minims  of  the  above  distillate  and 
let  stand  15  minutes.  Then  distil  off  about  J  of  the  quan- 
tity, and  to  the  distillate  add  Na2C03  in  slight  excess,  and 
boil  down  to  2  fl.  drams.  Then  acidulate  feebly  with 
HC2H302  and  add  1  grain  of  AgN03  in  30  minims  of  water  and 
heat  gently.  If  the  liquid  merely  darkens,  but  remains  trans- 
lucent, CH3OH  is  absent,  but  if  a  copious  ppt.  of  metallic 
silver  falls  and  a  thin  film  of  silver  lines  the  tube,  methyl 
alcohol  (CH3OH)  is  present. 

NOTE. — This  test    depends    upon  oxidizing  CH3OH   to 
formic  acid  (HCOOH),  which  reduces  silver. 

CH3OH  +  02  =  HCOOH  +  H20. 

The  ethyl  alcohol  present  is  oxidized  to  acetic  acid,  which 
does  not  reduce  silver.  Aldehyd,  which  is  produced  at 
the  same  time  and  which  does  reduce  silver,  is  removed  by 
boiling  with  Na2COs. 


QUALITATIVE   ANALYSIS  OF  ORGANIC  SUBSTANCES.     147 

Sieker's  Method  (Am.  Dr.,  Mch.  25,  '01,  and  Ph.  Rev.,  '01,  117). 
This  method  is  based  upon  the  oxidation  to  formalde- 
hyd  by  a  heated  copper-wire  spiral,  and  has  the  advantage 
of  rapidity.  Pour  4  to  8  rails  of  the  spirit  into  a  test- 
tube  and  warm  gently;  immediately  insert  into  the  tube 
(not  into  the  liquid)  a  copper-wire  spiral  which  has  been 
previously  heated  to  dull  redness;  withdraw  and  reinsert 
the  spiral  several  times,  and  it  will  be  observed  that  a 
strong  odor  of  formaldehyd  is  evolved,  while  the  spiral 
will  change  in  color  from  black  CuO  to  red  Cu  upon  in- 
serting it,  and  will  resume  its  black  color  each  time  it  is 
withdrawn  into  the  air. 

NOTE.  —  Heating  the  copper  wire  oxidizes  it  to  CuO. 
The  warm  methyl-alcohol  vapor  reduces  the  CuO  to  Cu 
and  is  itself  oxidized  to  formaldehyd. 

CH3OH  +  CuO  =  HCOH  +  H20  +  Cu. 

Ethyl  alcohol  reduces  CuO  in  the  same  manner,  but  the 
odor  of  formaldehyd  and  of  formic  acid  distinguishes  the 
methyl  alcohol. 

Acetaldehyd.  —  Colorless,  limpid,  inflammable,  possessing  a 
fruity  odor.  Boiling-point  20.8°  C.  Miscible  with  water, 
alcohol,  ether,  and  benzin. 

(1)  With  solution  of  Ag20  in  ammonia,  gives  a  bright 
mirror  of  silver  on  warming.     KOH  facilitates  the  reaction. 

(2)  It  reduces  Fehling's  solution  on  being  boiled,  deposit- 
ing a  red  ppt.  of  Cu20,  and  being  thus  converted  into  acetic 
acid: 


(3)  Heated  with  KOH  it  acquires  a  brown  color. 

(4)  Rosaniline  solution  bleached  by  S02,  gives  a  pinkish- 
violet  color  with  aldehyd. 


148  QUALITATIVE  CHEMICAL  ANALYSIS. 

Paraldehyd. — A  limpid  liquid,  colorless,  possessing  an  odor 
resembling  that  of  aldehyd.  Soluble  in  8  parts  of  water. 
Boils  at  124°  C.,  evolving  inflammable  vapors.  Distilled  with 
dilute  H2S04  it  is  again  converted  into  aldehyd,  of  which 
paraldehyd  is  a  polymer;  its  formula  is  CcH^Os  (which  is 
the  formula  of  aldehyd  (C2H40)  taken  three  times.) 

(1)  5  mils  boiled  with  5  mils  of  KOH  gives  no  brown 
color  (distinction  from  aldehyd). 

(2)  Heated    with    Ammonio-Argentic-Nitrate,    it    pro- 
duces a  mirror  of  metallic  silver. 

Formaldehyd,  Formalin,  Formic  Aldehyd  (CHOH). — Miscible 
with  water  and  alcohol,  possessing  a  pungent  odor  of  ham- 
amelis  extract;  highly  antiseptic  liquid. 

(1)  Hehner's  Test. — Mix  2  mils  of  highly  diluted  solution 
of  Formaldehyd,  with  2  mils  of  milk,  and  underlay  with  2 
mils  of  H2S04  containing  a  trace  of  Feds  (Tinct.  Ferri  chlor. 
1  part   and  C.  P.  H2S04  25  parts)  (Lyons)  as  carefully  as 
possible  =  violet-blue  zone.     Reaction  very  delicate. 

(2)  With  the  Morphine-sulfuric  Reagent  (Morphine  0.12 
gm.  in  strong  C.  P.,  H2S043mils).     Underlay  the  distillate 
(highly  diluted),  or  a  solution  of  CHOH  very  dilute  with  2 
mils  of  the  reagent;  a  purple-red  color  changing  to  violet  will 
form.     (By  mixing  3  drops  of  40%  Formaldehyd  with  3  mils 
of  pure  strong  H2S04,  a  reagent  is  obtained  which  gives  a 
similar  reaction  with  Morphine  (very  reliable) .) 

Five  mils  diluted  with  25  mils  of  water  and  heated  with 
3  mils  of  ammonio-argentic-nitrate  solution  =  a  gray  ppt.  of 
metallic  silver  and  a  deposit  of  silver  in  form  of  a  mirror  on 
sides  of  test-tube. 

To  a  little  H2S04  in  which  some  salicylic  acid  has  been 
dissolved,  the  addition  of  two  drops  of  formaldehyd  solu- 
tion will  produce  a  permanent  deep-red  color  on  warming. 
Ether,  Ethyl  Oxid. — A  colorless,  mobile,  highly  inflammable 
liquid  of  characteristic  odor,  boiling  at  35.5°  C.,  miscible 
with  10  times  its  volume  of  water,  and  very  readily  miscible 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.     149 

with   alcohol,    chloroform,    benzin,    benzene,    and   oils.     It 
dissolves  fats  and  resins. 

Acetic  Ether,  Ethyl  Acetate— A.  colorless,  limpid,  inflammable 
liquid,  possessing  a  fragrant  acetous  odor  resembling  that 
of  apples.  It  boils  at  72°  C.,  and  is  miscible  in  all  propor- 
tions with  alcohol  and  with  7  parts  of  water. 

Boiled  with  KOH  solution  the  residue  gives  reactions  of 
acetates.  Distilled  with  KOH  solution  alcohol  is  produced, 
and  distils  over,  and  the  distillate  gives  the  reactions  for 
ethyl  alcohol: 

C2H5C2H302 + KOH  =  KC2H302  +  C2H5OH. 

168.    CLASS  A.    DIVISION    b.     LIQUIDS    NOT    MISCIBLE    WITH 

WATER. 

Chloroform,  Trichlor  Methane,  CHC13. — A  heavy,  clear,  colorless, 
mobile  liquid  of  a  characteristic  odor.  It  is  very  volatile, 
not  inflammable,  and  not  miscible  with  water. 

(1)  To  a  small  quantity  of  chloroform  in  a  test-tube 
add  some  alcoholic  solution  of  NaOH,  and  a  drop  or  two  of 
aniline,  and  warm  gently.    There  will  be  developed  a  very 
offensive  odor  of  phenylisocyanid. 

(2)  Boil  a  few  drops  of  chloroform  with  KOH  solution  and 
add  a  fragment  of  resorcinol.    An  intense  red  color  appears 
(rosolic  acid). 

(3)  A  few  drops  of  chloroform,  heated  with  a  solution  of 
betanaphthol  in  strong  KOH  solution  develops  a  fine  blue 
color,  changing  to  green  and  brown. 

Benzin,  Petroleum  Ether.— A  clear,  colorless  liquid,  of  a  strong 
characteristic  odor,  resembling  that  of  kerosene.  It  is  very 
inflammable,  and  is  not  miscible  with  water.  It  boils  at 
45°  to  60°  C. 

Benzene  =  Benzol  =  Coal-tar  Benzene.— A  limpid  liquid  possessing 
an  aromatic  benzin-like  odor.  Should  not  be  confounded 
with  petroleum  benzin. 


150  QUALITATIVE  CHEMICAL  ANALYSIS. 

Boiling-point  80°  C.  Miscible  with  alcohol,  ether  and 
chloroform,  insoluble  in  water.  Chemical  formula  CeHe. 

(1)  Mixed    with   strong   HN03    (avoiding    overheating) 
nitrobenzene  (oil  of  mirbane),  C6H5N02,   is  formed,  which, 
poured  into  cold  water,  separates  in  oil  drops  possessing 
the  characteristic  odor  of  essential  oil  of  bitter  almonds. 

(2)  Mixed  with  strong  H2S04  and  boiled  with  KOH, 
a  phenolsulfonate  is  obtained  which  should  be  tested  for. 
(Paragraph  138.) 

Amylic  Alcohol  (Fusel  Oil).  A  limpid  oily  liquid  possessing 
the  odor  of  whiskey;  miscible  with  alcohol,  but  very  spar- 
ingly with  water.  Boils  at  127°  C. 

(1)  Warmed    with    dilute    H2S04    and    NaC2H302,    it 
forms  amyl  acetate  ^Hi^HsC^)  possessing  the  odor  of 
pears,  and  known  as  "  pear  oil." 

(2)  Distilled  with  H2S04  and  K2Cr207  and  the  distillate 
boiled   with   KOH,    it   forms    potassium   valerate.    Apply 
the  tests  for  valerates.     (Paragraph  153.) 

Amyl  Nitrite,  CsHnNC^. — A  clear  yellowish  liquid  of  an  ethereal 
banana-like  odor. 

Insoluble  in  water.  Freely  miscible  with  alcohol  or  ether, 
very  volatile  even  at  low  temperature  and  very  inflammable, 
burning  with  a  smoky  flame. 

Add  2  mils  H2S04  to  a  mixture  of  2  drops  of  amyl  nitrite 
and  2  drops  of  H20.  Amyl  valerate  is  formed,  and  is  rec- 
ognized by  its  odor,  on  diluting  with  H20. 

When  mixed  with  potassium  iodid  and  a  drop  or  two  of 
sulfuric  acid,  iodin  is  liberated,  and  colors  starch  paste  blue. 

A  few  drops  of  amyl  nitrite  added  to  a  mixture  of 
1  mil  FeS04  T.S.  and  5  mils  of  dil.  HC1  =  a  greenish-brown 
color. 

Benzaldehyd,  Benzoic  Aldehyd. — A  colorless,  strongly  refrac- 
tive liquid  having  an  odor  like  that  of  essential  oil  of  bitter 
almonds.  Insoluble  in  water.  It  is  converted  into  ben- 
zoic  acid  by  oxidation. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    151 

169.  CLASS  B. 

Phenol,  Carbolic  Acid — Phenic  Acid. — The  liquefied  carbolic 
acid  is  a  colorless  liquid  having  a  peculiar  characteristic 
aromatic  odor,  miscible  with  water,  and  readily  sol.  in 
alcohol,  ether,  chloroform  and  the  alkalies.  It  cauterizes 
and  whitens  the  skin  when  concentrated. 

Creosote,   an  almost   colorless  or  yellowish   (pinkish  or 


PHENOL. 


The  Bromin  Test. — Its  aqueous  sol. 
yields  with  bromin-water  a  white 
ppt.  of  tribromphenol,  which  at  first 
redissolves,  but  on  adding  more  of 
the  reagent  becomes  permanent. 

The  Ferric  Chlorid  Test. — 10  mils  of 
an  aqueous  solution  of  phenol 
(1  :  100)  +  1  drop  of  FeCls  solution. 
The  solution  becomes  violet-blue, 
and  the  color  is  permanent. 


The  Collodion  Test. — Equal  volumes  of 
phenol  and  collodion,  stirred  to- 
gether in  a  dry  test-tube,  will  form 
a  permanent  coagulum.  This  also 
occurs  with  albumen. 

The  Glycerin  Test. — 1  volume  of  cold 
liquefied  phenol  forms  with  1  vol- 
ume of  glycerin  a  clear  liquid,  which 
is  not  rendered  turbid  on  the  addi- 
tion of  3  volumes  of  water. 


The  KOH  Test. — Does  not  correspond 
to  KOH  test  under  Creosote. 


Solidification  Test. — Phenol  solution 
solidifies  when  cooled. 

4  parts  of  phenol  solution  mixed  with 
1  part  of  NH4OH  and  a  few  drops 
of  NaCIO  added  and  gently  warmed 
=  a  blue  to  green  color. 

Add  H2SO4  to  some  benzaldehyd  until 
the  latter  darkens,  then  add  some 
phenol,  and  a  red  color  is  produced; 
now  add  some  KOH =a  violet  color. 


CREOSOTE. 


The  Bromin  Test. — Its  aqueous  solu- 
tion yields  with  bromin-water  a 
reddish-brown  ppt. 


The  Ferric  Chlorid  Test.—W  mils  of 
an  aqueous  solution  of  creosote 
+  1  drop  of  FeCl3  T.S.:  the  liquid 
develops  a  violet-blue  tint,  which  is 
transient,  changing  rapidly  to  green- 
ish and  brown,  and  forming  a 
brown  ppt. 

The  Collodion   Test. — No  permanent 

coagulum  results,  if  equal  parts  of 

•creosote  and  collodion  are  mixed. 


The  Glycerin  Test. — 1  volume  of  creo- 
sote forms  with  1  volume  of  glycerin 
a  clear  liquid,  from  which  J  volume 
of  water  will  cause  separation  of  a 
creosotic  layer  equal  to  more  than 
1  volume  and  render  the  liquid 
turbid. 

The  KOH  Test.— I  mil  of  creosote 
mixed  with  10  mils  of  KOH  in  abso- 
lute alcohol  (1  :5)=a  solid  crys- 
talline mass. 

Solidification  Test. — Creosote  cooled 
to  —  4°  F.  does  not  solidify,  but  it 
gelatinizes. 


152  QUALITATIVE  CHEMICAL  ANALYSIS. 

brown  if  impure),  highly  refractive,  oily  liquid  having  a 
penetrating,  smoky  odor;  soluble  in  HC2H302. 
Glycerin.  Glycerol  Propenylakohol. — A  clear,  colorless,  thick, 
syrupy  liquid,  smooth  to  the  touch,  sweet  to  the  taste, 
odorless,  producing  a  sensation  of  warmth  hi  the  mouth. 
It  absorbs  moisture;  soluble  in  all  proportions  in  water  and 
alcohol,  but  not  soluble  hi  ether,  chloroform,  carbon  disulfid, 
benzin  or  oils. 

(1)  The  Borax-bead  Test.    Add  a  few  drops  of  glycerin 
to  a  little  powdered  borax;  mix  and  dip  the  looped  end  of  a 
platinum  wire  into  the  mixture,  and  hold  hi  a  Bunsen  flame = 
a  transient  green  color. 

(2)  The  Acrokin  Test. — Heated  alone  or  with  .5  Gm.  of 
potassium  bisulfate  to  a  high  temperature  an  irritating  odor 
of  acrolein  is  produced. 

(3)  The  Borax  Test. — A  piece  of  blue  litmus  paper  is 
shaken  in  a  test-tube  with  a  solution  of  borax,  and  a  few 
drops  of  glycerin  added.    The  litmus  paper  immediately 
becomes  red.    This  is  due  to  the  liberation  of  boric  acid  by 
the  glycerin.    The  addition  of  a  little  bicarbonate  of  soda 
to  this  mixture  will  cause  effervescence. 

(4)  The   Permanganate  Oxidation   Test. — Glycerin  in   a 
strongly  alkaline  solution  is  oxidized  by  KMn(>4  and  con- 
verted into  oxalic  acid. 

Take  1  mil  of  a  weak  solution  of  glycerin,  make  it  strongly 
alkaline  with  KOH,  and  add  an  excess  of  a  saturated  solution 
of  KMnCU,  i.e.,  until  the  mixture  is  blackish.  Boil  and 
add  some  Na2S03  to  destroy  excess  of  KMn04,  then  filter, 
acidulate  with  HC2H302  and  add  CaCl2=a  white  ppt.  of 
CaC204  forms : 
C3H5(OH)3+4KMn04=K2C204+K2C03+4Mn02+4H20 

Potassium 
Oxalate. 

K2C204 + CaCl2 = CaC204 + 2KC1. 

Calcium 
Oxalate. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    153 

Nitrobenzene  =  Nitrobenzol  (Oil  Mirbane) .  A  limpid,  yellowish, 
oily  liquid,  possessing  the  odor  of  essential  oil  of  bitter 
almonds. 

(1)  Placed  in  contact  with  zinc  dust  and  dilute  H2S04, 
it  is  decomposed  into  aniline  and  water: 

C6H5N02 + 3H2  =  C6H5NH2 + 2H20. 

(2)  Heat  the  aniline  solution  as  obtained  above  with 
a  few  drops  of  CHCla  and  KOH.     The  characteristic  odor  of 
phenylisocyanid  will  be  recognized. 

(3)  Drop  a  small  crystal  of  KC103  into  some  nitrobenzene, 
and  underlay  this  with  H2S(>4;  a  violet  color  will  develop. 


154  QUALITATIVE  CHEMICAL  ANALYSIS. 

170.  IDENTIFICATION  OF  SCALED  IRON  COMPOUNDS  * 

STEP  I. — Heat  about  1  gram  of  the  substance  in  a  porcelain 
crucible  to  dull  redness,  allowing  free  access  of  air. 

If  an  odor  resembling  that  of  burning  sugar  is  given  off,  the 
substance  is  probably  a  citrate  or  tartrate.  Confirm  in  Step  IV. 

When  all  the  combustible  matter  is  consumed,  dissolve 
out  the  soluble  part  of  the  residue  with  a  few  mils  of  hot  water, 
and  filter. 

Test  the  filtrate  with  red  litmus  paper. 

The  paper  turns  blue;  sodium  or  potassium,  or  both  are 
present. 

The  paper  remains  unchanged  in  color;  proceed  to  Step  II. 

Divide  the  solution  which  has  turned  red  litmus  blue  into 
two  parts. 

(a)  Heat  on  a  clean  platinum  wire  in  a  colorless  flame :  The 
flame  becomes  intensely  yellow;    sodium  is  present.     Observe 
this  flame  through  cobalt  glass.     If  violet-red,  potassium  also 
is  present. 

.    The  flame  is  colored  violet  only;  potassium  is  present.     Con- 
firm under  (fe). 

(b)  Add  to  the  solution  some  test  solution  of  sodium-cobaltic 
nitrite : 

A  copious  yellow  precipitate  indicates  potassium. 

STEP  II. — Dissolve  a  small  quantity  of  the  original  sub- 
stance in  water,  acidulate  with  hydrochloric  acid  and  divide 
into  two  parts.  To  one  part  add  test  solution  of  potassium 
ferrocyanid: 

A  blue  precipitate  indicates  ferric  iron. 

To  the  other  part  add  potassium  ferricyanid : 

A  blue  precipitate  indicates  ferrous  iron. 

STEP  III. — Dissolve  2  grams  of  the  original  substance  in 

*  Joseph  L.Mayer,  Drugg.Cir.,  Feb.  1901. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    155 

20  mils  of  10%  solution  of  potassium  hydroxid  and  boil;  an 
odor  of  ammonia  indicates  the  presence  of  ammonium. 

Whether  ammonium  is  present  or  not,  cool  the  solutior 
and  filter;  examine  the  filtrate  as  directed  in  Step  IV,  and 
the  precipitate  as  in  Step  V. 

STEP  IV. — The  filtrate  obtained  in  Step  III  should  be  clear 
and  colorless  and  measure  about  10  mils.  Divide  it  into  three 
portions  of  2.5,  2.5  and  5  mils,  respectively. 

(a)  Slightly  acidulate  one  of  the  smaller  portions  with  acetic 
acid  and  add  test  solution  of  calcium  chlorid: 

A  precipitate  occurs;  the  salt  is  probably  a  pyrophosphate. 
Confirm  by  (c) . 

Filter  and  boil  the  filtrate  (or  the  clear  solution  if  no  pre- 
cipitation has  occurred) : 

A  white  crystalline  precipitate  occurring  after  a  few  minutes 
indicates  a  citrate. 

(b)  Slightly   acidulate   the    second   smaller   portion   with 
acetic  acid  and  add  an  equal  volume  of  alcohol : 

A  white  crystalline  precipitate  occurring  after  a  few  minutes 
indicates  a  tartrate. 

(c)  To  the  remaining  portion  of  (5  mils)  add  5  mils  of  a  10% 
solution  of  ammonium  chlorid,  and  then  add,  a  few  drops  at 
a  time,  1.5  mils  of  a  10%  solution  of  magnesium  sulfate,  agitating 
after  each  addition: 

A  white  crystalline  precipitate  indicates  a  phosphate. 

Confirm  as  follows:  Thoroughly  wash  the  precipitate  until 
the  wash-water  gives  no  cloudiness  with  silver-nitrate  solu- 
tion, dissolve  in  dilute  nitric  acid,  neutralize  with  ammonium 
hydroxid,  acidify  with  acetic  acid  and  add  5%  solution  of 
silver  nitrate. 

If  a  phosphate  is  present,  a  canary-yellow  precipitate  appears. 

To  the  filtrate  from  the  precipitate  obtained  by  the  addi- 
tion of  ammonium  chlorid  and  magnesium  sulfate  to  (c),  or  to 
the  clear  liquid  if  no  precipitate  was  produced,  add  a  little 
acetic  acid  and  heat  to  boiling: 


156  QUALITATIVE   CHEMICAL  ANALYSIS. 

A  white  flocculent  precipitate  indicates  a  pyrophosphate. 

Confirm  by  the  silver-nitrate  test  applied  as  above : 

A  white  precipitate  appears  if  a  pyrophosphate  is  present. 

STEP  V. — Wash  the  precipitate  obtained  in  Step  III.  into 
a  test-tube  with  about  15  cc.  of  chloroform,  shake  well  for  a 
few  minutes,  filter,  and  divide  the  filtrate  into  two  portions 
(a)  and  (&).  Heat  both  portions  of  the  filtrate  in  porcelain 
capsules  on  a  water-bath  until  the  chloroform  is  all  evaporated. 

(a)  Add  a  small  quantity  of  hot  water  slightly  acidulated 
with  sulfuric  acid  to  the  residue  in  one  of  the  capsules,  and 
filter.     Divide  the  filtrate  into  three  equal  parts. 

1.  Add  to  one  portion,  Mayer's  reagent: 
A  precipitate  indicates  an  alkaloid. 

2.  Add  to  the  second  portion,  Labarraque's  solution,  using 
a  quantity  sufficient  to  destroy  blue  fluorescence  if  observed, 
and  then  a  few  drops  of  ammonium  hydroxid : 

An  emerald-green  color  indicates  quinine. 

3.  To  the  third  portion  add  ammonium  hydroxid  in  slight 
excess,   filter,   reject   the  filtrate,   dissolve   the   precipitate   in 
about  1  mil  of  water,  containing  a  few  drops  of  diluted  acetic 
acid,   neutralize  exactly  with   potassium   hydroxid,    and   add 
about  1  mil  of  a  saturated  solution  of  Rochelle  salt: 

A  white  precipitate  indicates  quinine  or  cinchonidine. 

Filter  off  the  precipitate,  dissolve  in  diluted  hydrochloric  acid, 
add  potassium-hydroxid  solution  and  2  mils  of  ether,  and  shake 
well.  The  quinine  dissolves,  while  the  cinchonidine  remains  as  a 
crystalline  precipitate  at  the  line  of  separation  of  the  two  liquids. 

To  the  filtrate  from  the  precipitate  in  3,  or  the  clear  solu- 
tion if  no  precipitate  was  produced,  add  an  excess  of  potassium 
hydroxid: 

A  white  precipitate  insoluble  in  ether  indicates  cinchonine. 

(b)  To  the  residue  in  the  other  capsule  add  a  drop  of  sulfuric 
acid;  into  this  put  a  fragment  of  potassium  dichromate,  and  after 
a  few  minutes  draw  this  drop,  by  means  of  a  glass  rod,  across 
the  capsule: 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    157 

A  beautiful  violet  color,  changing  quickly  to  yellow  and  red, 
indicates  strychnine. 

NOTES. — As  the  foregoing  scheme  is  intended  partly  for  the 
benefit  of  students,  I  add  some  notes  regarding  the  chemistry 
involved  in  its  construction. 

STEP  I. — When  organic  salts  of  the  alkali  metals  are  ignited, 
they  leave  their  carbonates,  which  affect  red  litmus  paper; 
the  qualitative  reactions  then  separate  the  two. 

STEP  II. — This  introduces  the  qualitative  reaction  for  fer- 
rous and  ferric  iron. 

STEP  III. — This  depends  upon  the  fact  that  compounds 
containing  ammonium  give  off  ammonia  when  brought  in  con- 
tact with  an  alkali  hydroxid.  In  addition,  this  step  plays  the 
role  of  precipitating  the  iron  as  a  hydroxid,  thus  making  it 
possible  to  operate  with  a  colorless  filtrate  in  Step  IV.  It 
then  goes  farther  by  rendering  Step  V  assistance  by  precipi- 
tating the  alkaloids  and  keeping  them  in  the  iron  magma  until 
the  time  arrives  to  proceed  with  their  identification.  The  alka- 
loidal  salts  when  treated  with  an  alkali  give  up  their  acid  and, 
being  insoluble  in  the  solution,  they  precipitate.  Upon  this 
fact  the  process  depends.  It  is  easy  to  see  that  the  alkaloids 
remain  on  the  filter,  while  the  acidulous  radicals  appear  as 
potassium  salts  in  the  filtrate. 

STEP  IV. — The  rationale  of  this  step  is  simple.  The  object 
of  adding  acetic  acid  is  to  prevent  the  precipitation  of  calcium 
citrate  in  the  cold.  This  is  made  necessary  through  the  fact 
that  pyrophosphates  (most  "iron  pyrophosphates"  are  citro- 
pyrophosphates)  produce  with  calcium- chlorid  test  solution  a 
precipitate  insoluble  in  acetic  acid,  whereas  the  citrate  pre- 
cipitate is  soluble;  if  therefore  acetic  acid  is  first  added,  the 
citrate  remains  unaffected  until  the  solution  is  boiled.  There- 
fore if  a  precipitate  forms  in  the  cold,  filter  and  test  the  filtrate 
as  directed.  Unless  there  be  an  excess,  the  citrate  precipitate 
does  not  form  in  the  cold,  but  calcium  citrate,  being  insoluble 
in  hot  solution,  precipitates  when  the  solution  is  boiled. 


158  QUALITATIVE   CHEMICAL  ANALYSIS. 

If  the  filtrate  containing  potassium  hydroxid  also  contains 
a  tartrate,  the  addition  of  acetic  acid  produces  potassium  acid 
tartrate  which  is  practically  insoluble  in  water,  and  totally 
insoluble  in  alcohol. 

Phosphates  produce  with  magnesia  mixture  the  white 
crystalline  ammonio-magnesium  phosphate  and  as  pointed 
out  by  Nagelvoort  (Am.  Journ.  Pharm.,  1895,  page  210)  an  excess 
of  magnesia  mixture  is  objectionable  and  apt  to  lead  to  erroneous 
conclusions.  The  magnesia  mixture  is  prepared  in  the  course 
of  the  process,  acting  upon  the  suggestion  of  Steiglitz  (Am. 
Journ.  Pharm.,  1891,  page-  583),  as  follows:  The  nitrate  con- 
taining potassium  hydroxid  has  added  to  it  ammonium-chlorid 
solution,  whereupon,  as  shown  in  a  previous  reaction,  ammonium 
hydroxid  is  generated.  There  remains,  however,  enough  am- 
monium chlorid  in  the  solution  to  prevent  precipitation  of  mag' 
nesium  hydroxid  when  the  magnesium-sulfate  solution  is  added. 
Having  subjected  the  sample  to  the  test  and  obtaining  what 
gives  every  evidence  of  being  a  phosphate,  the  reaction  with 
silver  nitrate  acts  in  a  confirmatory  manner.  Orthophosphates 
give  with  this  reagent  a  yellow  precipitate  and  pyrophosphates 
a  white  one.  The  separation  of  the  pyrophosphate  from  the 
phosphates  is  made  possible  in  this  step  as  a  result  of  the  fact 
pointed  out  by  Fresenius,  that  pyrophosphates  produce  with 
magnesium  sulfate  a  precipitate  of  magnesium  pyrophosphate 
soluble  in  excess  of  magnesium  sulfate  and  not  precipitated  by 
ammonium  hydroxid,  which,  being  the  contrary  of  the  behavior 
of  orthophosphates,  serves  to  separate  the  two  acids.  The 
nitrate  from  the  phosphate  precipitate,  or  the  solution  in  which 
the  reagent  has  produced  no  effect,  is  then  acidified  with  acetic 
acid  and  heated  to  boiling:  a  white  flocculent  precipitate  in- 
dicates a  pyrophosphate. 

STEP  V. — The  fact  upon  which  this  step  is  based  has  been 
partly  explained  in  Step  III.,  where  the  alkaloids  remained  in 
the  magma,  and  being  soluble  in  chloroform,  that  solvent,  after 
being  thoroughly  shaken  with  the  residue,  takes  them  up.  By 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    159 

treating  the  residue  with  hot  water  containing  a  few  drops  of 
diluted  sulfuric  acid,  the  sulfates  of  the  alkaloids  are  formed, 
and  being  more  soluble  in  hot  water  than  in  cold,  the  process 
directs  that  condition.  Mayer's  reagent  precipitates  all  the 
alkaloids  included  in  the  scheme,  and  if  no  reaction  occurs, 
their  absence  is  safely  reported. 

The  test  for  quinine  is  made  with  Labarraque's  solution, 
and  as  this  is  a  new  method  a  word  regarding  it  will  not  be 
amiss.  Every  one  who  has  had  occasion  to  qualitatively  test 
for  quinine  with  chlorine  or  bromin  water  must  know  the  diffi- 
culties encountered  through  the  inconvenience  of  obtaining 
either  of  the  above  two  reagents  in  a  condition  to  be  depended 
upon.  The  Labarraque's  solution  is  always  at  hand.  The 
chemistry  concerned  in  the  reaction  is  easily  understood: 
The  Labarraque's  solution  coming  into  contact  with  the  acid 
of  the  solution  under  examination  has  its  chlorin  liberated, 
which,  if  quinine  is  present,  forms  with  it  and  a  few  drops  of 
ammonia  the  characteristic  thalleoquin — shown  by  an  emerald- 
green-colored  solution.  Having  in  many  qualitative  quinine 
determinations  applied  the  test  as  above  directed,  with  the 
most  satisfactory  results  the  writer  has  no  hesitation  in  advo- 
cating its  use  in  preference  to  the  others  referred  to. 

It  might  be  of  interest  to  here  mention  that  quinidine  also 
gives  a  green  color  with  this  test,  but  as  its  higher  price  precludes 
any  possibility  of  its  ever  being  substituted  for  quinine,  it  is 
unnecessary  to  point  out  the  method  of  differentiation. 

The  cinchonidine  reaction  is  dependent  upon  the  fact  that 
sodium  and  potassium  tartrate  (Rochelle  salt)  produces  with 
it  the  insoluble  cinchonidine  tartrate.  Quinine  behaves  in  a 
similar  manner  towards  this  reagent,  but  the  identification 
in  solution  2  of  this  step  eliminates  that  source  of  error.  If 
necessary,  the  alkaloid  can  in  the  event  of  a  doubt  be  further 
identified  as  directed. 

Cinchonine  is  identified  by  its  behavior  towards  ether. 
Potassium-hydroxid  precipitates  it;  ether  is  added  and  the 


CALIFORNIA  COLLE6K 

of    PHARMACY 


160  QUALITATIVE  CHEMICAL  ANALYSIS. 

cinchonine  being  insoluble,  remains  as  a  white  bulky  pre- 
cipitate. 

In  another  portion  of  the  residue  the  strychnine  is  identified. 
The  reaction  is  characteristic,  and  if  applied  as  directed  will 
detect  minute  quantities. 

The  entire  process  is  simple,  accurate,  inexpensive  to  operate, 
quickly  carried  out,  and  has  everything  to  commend  it. 


171.  A  SCHEME  FOR  THE   DETECTION   OF   POISONS. 

Divide  the  suspected  sample  into  3  parts,  A,  B,  and  C,  and 
treat  as  follows : 

A.  (1)  If  a  liquid,  place  in  a  capsule,  and  on  a  water-bath 
evaporate  to  a  syrupy  consistency 

(2)  If  a  solid,  chop  up  or  cut  up  with  scissors  into  smallest 
possible  pieces. 

(3)  Transfer  product  of  either  (1  or  2),  to  a  flask  provided 
with  a  reflux   (upright  Liebig's)  condenser  or  a  long 
tube  drawn  through  the  cork  of  flask.     Cover  the  sub- 
stance with  twice  its  bulk  of  a  1%  solution  of  tartarir 
acid  in  alcohol,  and  heat  on  a  water-bath  for  one  hour 
(Stas-Otto). 

(4)  Remove  from  the  water-bath,  cool,  filter,  and  carefully 
concentrate  the  filtrate  on  a  water-bath  until  all  the 
alcohol  is  dissipated. 

(5)  Filter    the    concentrated    extract    through    a    wetted 
filter  and  again  evaporate  on  water-bath  to  a  syrupy 
consistency. 

(6)  Dissolve  the  syrupy  extract  in  absolute  alcohol,  stirring 
carefully  to  aid  in  effecting  as  complete  a  solution  as 
possible.      Filter  once  more,  and  again  drive  off  the 
alcohol  on  the  water-bath. 

(7)  Dissolve  the  residue  from  (6)  in  distilled  water,  render 
alkaline  with  sodium  hydroxid,  pour  into  a  separatory 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    161 

funnel,  and  extract  it  with  ether,  making  at  least  two 
'  extractions. 

(8)  Divide  the  ethereal  extract  from  (7)  into  two  portions, 
each  contained  in  an  evaporating  dish,  and  allow  the 
ether  to  volatilize  spontaneously;  the  alkaloids,  strych- 
nine, and  veratrine  should  be  tested  for  according  to 
Chart  89,  Steps  2  and  3,  respectively,  in  one  of  the 
dishes,  and  in  the  other  atropine  and  cocaine  should 
be  tested  for  according  to  Step  2. 

(9)  The  residue  from  the  separatory  funnel  is  poured  into 
an  evaporating  dish,  NH4OH  added  until  ammoniacal, 
and  placed  on  a  water-bath,  heating  it  until  all  the 
remaining  ether  is  dissipated,  and  then  set  aside  for 
12  hours. 

(10)  After  12  hours,  warm  the  product  of  (9),  pour  into  a 
separatory  funnel,  and  extract  it  with  amylic  alcohol. 
The  amylic  alcohol  extract  is  carefully  evaporated  in 
a  porcelain  capsule  and  morphine,  identified  as  in 
Step  1,  Chart  89. 

B.  (1)  Stir  this  portion  prepared  just  as  in  A  (1)  and  (2), 
with  about  200  mils  of  distilled  water,  and  acidify  (if  alka- 
line or  neutral,  not  otherwise)  with  1  or  2  mils  HC1  (C.  P.). 

(2)  Place  the  solution  prepared  as  in  (1)  on  a  dialyzer  and 
float  it  in  a  liter  of  distilled  water  contained  in  a  porcelain 
vessel. 

(3)  After  24  hours,  concentrate  the  water  in  the  porcelain 
dish  by  evaporation  on  a  water-bath.     (This  method 
separates   from   amorphous   organic   matter  any  crys- 
talloid substance,  be  it  inorganic  or  organic.) 

(4)  Divide  the  dialyzed  extract  (evaporated  to  about  50  mils 
in  (3))  into  two  equal  portions. 

Test  1st  portion  for  As,  Hg,  Sb,  Zn,  Pb,  with  H2S. 
Test  2d  portion  for  Phenol,  Chloral,  Chloroform,  Aniline, 


162  QUALITATIVE  CHEMICAL  ANALYSIS. 

Nitrobenzene,    Hydrocyanic    Acid,    Acetanilide,    Phe- 
nacetin  and  the  mineral  acids. 

C.  (1)  Prepare  as  in  A  ((1)  and  (2)) ;  place  in  an  evaporating 
dish,  add  an  equal  bulk  of  strong  pure  HC1,  and  warm 
on  the  water-bath,  from  time  to  time  adding  a  crystal  of 
KNOs  and  replacing  water  lost  on  evaporation.  Con- 
tinue until  all  the  organic  matter  is  destroyed,  expel 
chlorin  by  a  higher  heat,  pass  H^S  in  the  warm  solution, 
and  test  precipitate,  according  to  the  tables,  for  inor- 
ganic substances  and  the  acids  (except  HC1). 


172.  A  SCHEME   FOR  URANALYSIS. 

Observe: 

1.  Quantity  passed  in  24  hours.     It  should  be  from  1200 
to  1500  mils. 

2.  Color    and   transparency. — Colorless,    yellow    to    brown, 
clear,  cloudy  or  opaque. 

3.  Reaction. — Acid,  alkaline   or   arnphoteric;   normal   urine 
is  faintly  acid. 

4.  Specific  Gravity.— Should  be  1.015  to  1.025  at  15°  C. 

5.  Sediment. — Note  its  quantity,  and  examine  its  character 
with  a  microscope. 

NOTES:  1.  When  it  is  directed  to  warm  the  urine  do  not  boil. 

2.  If  not  perfectly  clear,  the  urine  should  be  filtered  before 
applying  tests. 

3.  If  much  albumin  is  present,  it  should  be  removed  before 
testing  for  sugar. 

4.  Putrid  urine  should  not  be   tested  for  sugar  by  any 
reagent  containing  copper  or  bismuth. 

5.  If  the  quantity  of  U  (abbreviation  used  in  this  scheme 
for  urine)  is  too  small  to  float  the  urinometer,  it  may  be  diluted 
with  an  equal  volume  of  water,  and  the  last  two  figures  of 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.     1Q3 

the  specific  gravity  of  this  diluted  urine,  multiplied  by  two,  or 
the  specific  gravity  may  be  taken  by  a  specific-gravity  bottle. 

6.  To  calculate  the  quantity  of  total  solids  from  the  specific 
gravity,  multiply  the  last  two  figures  of  the  specific  gravity 
by  2.33.  This  will  give  the  number  of  grms.  in  1000  mils  of 
urine.  The  last  two  figures  also  indicate  approximately  the 
number  of  grains  in  a  fluid  ounce. 

ORGANIC  CONSTITUENTS  (Abnormal): 

173.  Albumin. 

(a)  Heat  Test. — Add  10  drops  of  strong  acetic  acid 
to  10  mils  of  U.  Heat;  cloudiness  or  precipitate,  if 
any,  indicates  albumin. 

(6)  Nitric-acid  Test. — Heller's.  Put  2  mils  of  colorless 
HNOs  into  a  test-tube,  incline  the  tube,  and  add 
slowly,  by  means  of  a  pipette,  4  mils  of  U. 

A  sharp  white  band  (zone)  at  point  of  contact 
indicates  albumin. 

Precautions. 

1.  Mixed  urates  if  present  in  excess  will  also 
give  a  band  higher  up.     It  is  dissipated  by  warming 
(not  boiling). 

2.  After  the  administration  of  resinous  drugs 
(copaiba,  etc.)  or  turpentine,  a  yellowish  clouded 
zone  also  forms,  which  is  redissolved  by  alcohol 
(albumin  zone  does  not  dissolve). 

(c)  Tanret's  Test. — Acidify  5  mils  of  U  with  acetic  acid, 
add  Tanret's  reagent  drop  by  drop  until  2  mils  have 
been  added.  Then  warm.  Any  ppt.  remaining  is 
albumin. 

Precaution. 

This  test  precipitates  also  peptone,  alkaloids, 
urates,  and  pine  acids,  which,  however,  redissolve  on 
warming. 


164  QUALITATIVE  CHEMICAL  ANALYSIS. 

(d)  Potassium-ferrocyanid  Test. — Take  half  a  test-tube 
full  of  urine,  add  about  one-fourth  its  volume  of 
5  per  cent,  potassium-ferrocyanid  solution,  mix  well 
and  then  add  a  few  drops  of  acetic  acid.     If  albumin 
is  present  a  milky  cloud  will  appear  throughout  the 
whole  volume  of  the  liquid.    This  test  precipitates 
albumin  only. 

(e)  Quantitative  Estimation. — Fill  an  Esbach  albumino- 
meter  to  the  letter  "  U  "  with  urine,  and  then  to  the 
letter  "  R  "  with  Esbach's  reagent.     Cork  securely, 
mix  thoroughly,  by  carefully  inverting  tube,  and  set 
aside  for  24  hours — then  read.     Each  one  of  the 
main  divisions  read  off  indicates  1  grm.  of  albumin 
in  a  liter  of  urine. 

174.  Peptones. 

(a)  The  urine  is  slightly  acidulated  with  acetic  acid  and 
then  saturated  with  ammonium  sulfate.    The  pre- 
cipitate, if  any  (which  consists  of  albumin  and  the 
albumoses),  is  removed  by  filtration.    The  filtrate 
then  treated  with  Tanret's  reagent  ppts.  peptone 
only. 

(6)  Ralfe's  Test. — Place  4  mils  Fehling's  reagent  in  a 
test-tube,  and  gently  overlay  with  urine.  At  point 
of  contact  a  zone  of  phosphates  forms;  above  this 
another  rose-colored  zone,  or  "  halo,"  will  .float  if 
peptone  is  present. 
If  mixed  with  albumin  the  halo  will  be  purple. 

(b)  Randolph's  Test — To  5  mils  of  faintly  acid  urine  add 
4  drops  of  a  saturated  solution  of  KI  and  4  drops  of 
Millon's  reagent.     If   peptones    or  bile  acids  are 
present,  a  yellow  ppt.  falls.     Test  for  bile  acids;  if 
these  be  absent,  the  yellow  ppt.  indicates  peptones. 

175.  Glucose  (Sugar). 

(a)  Fehling's  Test. — Place  5  mils  of  Fehling's  reagent  in 
a  test-tube,  and  heat  to  boiling.    Add  now  drop 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    165 

by  drop  5  mils  of  urine,  heating  after  each  addition. 
A  yellow  or  orange  coloration  or  a  brick-red  ppt. 
of  copper  suboxid  (Cu20)  indicates  glucose. 

(b)  Pavy's  Test. — Place  5  mils  of  Pavy's  reagent  in  a  test- 
tube  and  warm.    Now  add  5  mils  of  U;  a  partial  or  a 
total  disappearance  of  the  blue  color  indicates  sugar. 

(c)  Haine's  Test. — Heat  5  mils  of  Haine's  reagent  in  a 
test-tube  to  boiling.     Drop  by  drop  add  6  to  8  drops 
of  U,  and  boil  again;   an  orange-red  ppt.  of  Cu20, 
indicates  glucose. 

(d)  Bdttger's  Bismuth  Test. — Place  in  a  test-tube  3  mils 
of  U,  3  mils  of  liquor  potassa  and  a  little  (0.3  grm.) 
bismuth  subnitrate;   boil  these  together  for  2  min- 
utes.  If  sugar  be  present  in  quantity,  black  metallic 
bismuth  deposits;  if  a  small  quantity  only  is  pres- 
ent the  solution  will  assume  a  grayish  color. 

(e)  Nylander's  Test. — Boil  together  in  a  test-tube  10  mils 
of  U  with  1  mil  of  Nylander's  reagent.     If  a  light- 
gray  or  black  precipitate  forms  it  indicates  glucose. 

(/)  Benedict's  Test. — (Qualitative). — Place  5  mils  of 
Benedict's  reagent  in  a  test-tube,  add  8  to  10  drops 
(not  more)  of  the  U  to  be  examined,  heat  to  vigor- 
ous boiling  and  keep  it  at  this  temperature  for  one 
or  two  minutes,  then  allow  the  mixture  to  cool 
spontaneously.  In  the  presence  of  glucose  the 
entire  body  of  the  solution  will  be  filled  with  a  precip- 
itate, which  may  be  red,  yellow  or  greenish  in  color. 
If  the  quantity  of  glucose  be  low  (under  0.3  per 
cent.)  the  precipitate  forms  only  on  cooling.  If  no 
.  glucose  is  present,  the  solution  remains  blue  and 
clear,  but  may  show  a  faint  turbidity. 

Dr.  J.  L.  Mayer  *  applies  the  test  as  follows: 
Into  a  very  small  Erlenmeyer  flask  introduce  5 
mils  of  Benedict's  reagent.    Then  by  means  of  a 
*  Journal  American  Pharmaceutical  Association,  1914,  page  687. 


166  QUALITATIVE  CHEMICAL  ANALYSIS. 

medicine  dropper  add  8  drops  of  U,  place  the  flask 
on  a  hot  plate  and  heat  to  boiling.  When  the  solu- 
tion starts  to  boil  time  it  for  1|  minutes,  and  then 
pour  it  into  a  test-tube  and  allow  it  to  cool  spon- 
taneously; a  greenish  tinge  extending  throughout 
the  solution,  upon  1J  minutes  boiling,  is  regarded 
as  a  positive  reaction.  If  the  greenish  color  does 
not  appear  until  the  liquid  has  cooled,  the  amount  of 
glucose  present  is  very  slight. 

(g)  Trommer's  Test. — Fill  the  test-tube  one-third  full  of 
U,  add  an  almost  equal  volume  of  10%  NaOH  solu- 
tion, and  then,  drop  by  drop,  CuSCU  T.S.,  until  the 
copper  hydrate  which  is  at  first  formed,  is  no 
longer  dissolved  on  shaking,  then  apply  heat.  A 
yellow  precipitate  of  cuprous  oxid  indicates  glucose. 

(h)  Phenyl-hydrazine  Test. — To  10  mils  of  the  U  in  a 
test-tube  add  1  gm.  of  phenyl  hydrazine  hydro- 
chlorid  and  2  gms.  of  sodium  acetate,  and  place  the 
test-tube  in  boiling  water  for  half  an  hour.  Then 
cool.  Crystals  of  phenyl-glycosazone  will  sep- 
arate and  when  viewed  under  a  microscope,  appear 
in  bundles  or  sheaves. 

(i)  Quantitative  Estimation  (by  Fermentation.) — Take 
jL  part  of  a  cake  of  Fleischmann's  yeast,  shake  thor- 
oughly with  10  mils  urine,  pour  into  an  Einhorn  sac- 
charometer,  and  set  aside  for  24  hours  in  a  room  of 
ordinary  temperature  (25°  C.  =  77°  F.).  Read  off 
the  percentage  of  glucose  present. 

(/)  Quantitative  Estimation  (with  Fehling's  Reagent).— 
Place  in  a  200-mil  flask  10  mils  of  Fehling's  solu- 
tion; to  this  add  10  mils  of  a  freshly  prepared  10% 
solution  of  K4Fe(CN)6  and  30  mils  of  water.  Heat 
mixture  on  a  water-bath  (best  temperature  for  the 
operation  being  between  80°  and  90°  C.) ;  then  run  in 
thell  (diluted  if  it  contains  much  sugar),  drop  by 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    167 

drop,  until  the  blue  color  just  disappears.  Excess 
of  glucose  quickly  turns  the  solution  yellowish-brown 
(copper  ferrocyanid  forms).  This  method  is  both 
reliable  and  rapid. 

(A:)  Quantitative  Estimation  (Benedict's). — Fill  a  burette 
with  the  U  diluted  1  : 10.  Then  introduce  25  mils  of 
Benedict's  Quantitative  Reagent  into  a  porcelain 
evaporating  dish  add  10  to  20  gms.  of  crystallized 
sodium  carbonate  and  a  small  quantity  of  powdered 
pumice  and  heat  to  boiling  over  a  free  flame,  until 
the  carbonate  is  entirely  dissolved.  Keep  the 
solution  boiling  vigorously,  and  run  the  U  rather 
rapidly  into  it  from  the  burette  until  a  chalk-white 
precipitate  forms  and  the  blue  color  of  the  solution 
begins  to  lessen  perceptibly,  after  which  deliver  the 
U  slowly,  a  few  drops  at  a  time,  until  the  last  trace 
of  blue  disappears.  This  marks  the  end  point. 

If  during  the  titration  the  solution  becomes  too 
concentrated,  through  evaporation,  add  water  to 
replace  the  volume  lost. 

The  calculation  of  the  quantity  of  glucose  in  the 
original  sample  of  urine  is  as  follows:  25  mils  of 
Benedict's  reagent  are  reduced  by  0.05  gm.  of  glu- 
cose. Therefore  the  volume  of  urine  required  to 
effect  the  reduction  contains  0.05  gm.  of  glucose. 
When  the  U  is  diluted  1  : 10  as  in  the  usual  titration 
of  diabetic  urines,  the  formula  for  calculating  the 
per  cent.. of  glucose  is 

—  xiooxio=%. 

*£ 

x  is  the  number  of  mils  of  diluted  U  employed  in 

the    titration   to    effect    the    complete   reduction. 

Dr.  Jos.  L.  Mayer  *  applies  the  method  as  follows: 

*  J.  A.  Ph.  A.,  1914,  page  688. 


168  QUALITATIVE  CHEMICAL  ANALYSIS. 

Into  a  100-mil  Erlemneyer  flask,  measure  25  mils  of 
Benedict's  Quantitative  Reagent,  add  about  10 
gms.  of  anhydrous  sodium  carbonate,  a  couple  of 
pieces  of  pumice  stone,  which  have  been  heated  to 
white  heat  and  plunged  into  water,  and  about  10 
mils  of  distilled  water.  Place  the  whole  on  a  hot 
plate  until  the  solution  boils  and  the  sodium  car- 
bonate is  dissolved.  Then  begin  adding  the  U  in 
small  amounts  from  the  burette,  allowing  sufficient 
time  between  each  addition  for  the  reaction  to  pro- 
ceed. The  end  reaction  is  known  by  the  disap- 
pearance of  the  last  trace  of  blue. 
176.  Indican  (Uroxanthine  Indoxyl-potassium  sulfate). 

(a)  Place  4  mils  of  HC1  in  a  test-tube,  add  an  equal  vol- 
ume cf  urine  and  a  few  drops  of  nitric  acid,  boil,  cool 
and  then  shake  with  a  few  drops  of  chloroform.  The 
latter  becomes  violet  if  excess  of  indican  is  present. 
(6)  Obermeyer'  s  Test. — Place  4  mils  of  urine  in  a  test-tube, 
add  an  equal  volume  of  hydrochloric  acid  containing 
FeCl3  (2  gm.  in  1000  cc.).  Shake  with  chloroform, 
and  a  violet-blue  color  occurs  in  the  latter. 
Precaution. 

If  biliary  acids  or  phosphates  are  present,  remove 
them  before  testing  for  indican  by  adding  to  10  mils 
of  U,  8  drops  of  Pb(C2H302)2  solution  and  filtering. 
The  nitrate  is  now  tested  for  indican. 
(c)  Place  in  a  test-tube  4  mils  each  HC1  and  U,  agitate, 
add  2  or  3  drops  of  a  very  dilute  solution  of  chlor- 
inated soda,  and  shake;  a  reddish-blue  or  bluish- 
black  coloration  indicates  indican  (indigo  is  formed 
in  this  reaction;  a  weak  solution  of  NaCIO  is 
directed,  as  an  excess  would  bleach  the  indigo). 
If  now  2  mils  of  CHCls  be  added  and  the  mixture 
agitated,  the  indigo  is  dissolved  out  and  with  the 
chloroform  settles  at  the  bottom  as  a  blue  bead  (the 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    169 

depth  of  the  blue  color  is  indicative  of  the  quantity 
of  indican  present). 

177.  Blood. 

(a)  Heller's  Test. — To  5  mils  of  U  contained  in  a  test- 
tube  add  2  mils  of  KOH  solution  and  warm. 

The  earthy  phosphates  which  precipitate  carry 
with  them  the  blood  coloring-matter,  and  if  blood 
is  present  the  precipitate  will  be  blood-red,  in  ab- 
sence of  blood,  white. 

(6)  Almeris  Test. — Shake  together  in  a  test-tube  5  mils 
each  of  tincture  guaiacum  and  hydrogen  dioxid 
(or  old  resinified  turpentine  oil),  and  drop  by  drop 
add  about  5  mils  of  U.  Let  stand  a  few  minutes;  if 
blood  is  present,  a  blue  or  bluish-green  coloration  is 
formed  in  the  upper  layer.  If  much  blood  is  present, 
on  agitating  the  tube  it  will  diffuse  through  the  entire 
liquid,  giving  it  a  creamy-bluish  color. 

178.  Bile. 

(a)  Gmeliris  Test  (for  bile  pigments). 

Place  into  a  narrow  test-tube  some  nitric  acid 
containing  a  little  yellow  nitrous  acid  (or  nitric  acid 
which  is  partly  decomposed  by  adding  a  fragment 
of  zinc,  or  a  piece  .of  wood  to  it),  and  carefully 
float  upon  this  about  an  equal  volume  of  urine. 
There  will  appear  in  the  middle  zone  a  play  of  colors 
from  below,  upward,  green,  blue,  violet,  red,  and 
yellow. 

This  test  may  be  modified  by  moistening  a  piece 
of  white  filtering  paper  with  the  urine  and  then 
placing  in  the  center  a  drop  of  nitric  acid  containing 
a  little  ntirous  acid.  A  pale  yellow  spot  is  formed, 
.  surrounded  by  colored  rings.  Instead  of  filtering 
paper  a  plaster  of  paris  disk  may  be  used. 

(6)  lodin  Test.— Upon  the  surface  of  5  mils  of  U,  care- 
fully float  10  drops  of  tincture  of  iodin,  which  has 


170  QUALITATIVE  CHEMICAL  ANALYSIS. 

been  diluted  with  alcohol  until  it  has  a  sherry  wine 
color.  At  the  point  of  contact  an  emerald-green 
zone  is  formed  if  bile  is  present. 

(c)  Pettenkofer's  Test  (for  Biliary  Acids). — Add  to  5  mils 
of  U  contained  in  a  test-tube  4  drops  of  a  solution  of 
cane-sugar  (saccharose  1:3),  shake,  and  carefully 
underlay  with  strong  H^SO^     Let  stand  for  a  few 
minutes;  if  biliary  acids  be  present,  a  purple  band 
is  formed  at  point  of  contact. 

(d)  Oliver's  Peptone  Test  (for  Biliary  Acids). — Clarify  the 
U  by  filtration,  and  dilute  to  the  sp.gr.  of  1.008. 
Place  in  a  test-tube  4  mils  of  Oliver's  reagent  and 
run  into  it  1  mil  of  the  U,  diluted  as  above.    If 
biliary    acids    are    present,    a    distinct    milkiness 
promptly   appears,   which  becomes  more   intense 
after  a  few  minutes.     Oliver's  reagent  is  composed 
of  pulverized  peptone,  2  gms.,   salicylic  acid,  0.25 
grm.;    acetic  acid,  2  mils;    and  sufficient  distilled 
water  to  make  250  mils. 

Precaution. 

The  above  test  is  very  delicate  and  reliable,  but 
only  in  the  absence  of  albumin,  which  should  be 
removed  by  boiling  the  U  with  a  few  drops  of 
HC2H302  and  filtering. 
179.  Acetone. 

(a)  Legal 's  Test. — Pour  into  a  test-tube  2  mils  of  a 
strong  freshly  prepared  solution  of  sodium  nitro- 
prussid,  and  add  4  mils  of  U  and  2  mils  NaOH  solu- 
tion. The  mixture  acquires  a  red  coloration,  which 
may  be  due  to  creatinin  (a  normal  constituent  of  U) 
as  well  as  to  acetone.  Add  6  or  8  mils  of  glacial 
HC2H302;  if  the  mixture  now  assumes  a  claret-red 
or  violet  color,  acetone  is  present  in  considerable 
quantity;  if  the  color  is  discharged  by  the  acid,  it 
was  due  to  creatinin  only. 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    171 

A  better  method  of  applying  this  test  is  to  add 
to  about  5  mils  of  urine  a  few  drops  of  freshly  pre- 
pared solution  of  sodium  nitroprussid,  then  make 
strongly  acid  with  glacial  acetic  acid  and  after  thor- 
oughly mixing,  carefully  float  some  strong  ammonia 
water  on  top — a  violet  zone  at  the  line  of  contact 
indicates  acetone. 

(b)  Lieben's  Test. — Pour  into  a  test-tube  6  mils  of  U, 
add  10  drops  solution  of  iodin  and  about  1  mil  of 
NH40H,  and  heat.    If  acetone  be  present,  crystals 
of  iodoform  will  form  and  deposit;  the  iodoform  may 
be  recognized  by  its  characteristic  aromatic  odor. 

(c)  Ehrlich's  Diazo  Reaction  for  Typhoid  Fever. — The 
reagent  consists  of  two  solutions:    No.  I.  Sodium 
nitrite  1  gm.  dissolved  in  distilled  water  to  make 
200  mils.     No.  II.  Sulphanilic  acid  5  gms.,  hydro- 
chloric acid  50  mils,  distilled  water  to  make  1000 
mils. 

For  use,  1  mil  of  No.  I  should  be  mixed  with  50 
mils  of  No.  II. 

The  test  is  applied  as  follows:  Take  a  portion 
of  the  reagent  mixed  as  above,  and  add  an  equal 
volume  of  U,  make  strongly  alkaline  with  am- 
monia water,  and  shake  well.  Both  the  foam  and 
the  solution  will  become  rose-colored,  and  a  greenish 
precipitate  will  be  observed  at  the  end  of  24  hours. 

ORGANIC  CONSTITUENTS  (Normal): 

180.  Urea  (Carbamid,  CH4N20),  Quantitative  Estimation  of. 
(a)  Fill  a  Doremus  ureometer  to  the  double  mark  with 
hypobromite  solution  (made,  by  dissolving  100  gms. 
of  NaOH  in  250  mils  of  water,  and  to  this  adding 
25  mils  of  bromin),  then  add  enough  water  to  half 
fill  the  bulb.  Now  add  1  mil  of  U  by  means  of  a 
nipple-pipette,  forcing  it  as  far  up  into  the  graduated 


172  QUALITATIVE  CHEMICAL  ANALYSIS. 

cylinder  as  possible,  stopper  securely,  let  stand  15 
minutes  or  until  all  the  nitrogen  is  evolved,  then 
read  off,  grains  per  fl.  oz.  or  gms.,  per  1000  mils. 
(b)  A  better  instrument  for  this  estimation  is  the  Hind's 
modification  of  the  Doremus  ureometer.  This 
instrument  is  provided  with  a  side  arm,  graduated 
to  deliver  one  or  two  mils  of  urine,  a  glass  stop-cock 
is  situated  in  the  lower  part  of  the  short  arm,  and 
this  when  open  permits  the  urine  to  flow  into  the 
long  arm  of  the  instrument  where  the  reaction  takes 
place. 

181.  Uric  Acid,  C5H4N403. 

(a)  Murexid  Test.— Evaporate  10  mils  of  U  to  dryness  in 
a  porcelain  capsule,  and  then  add  a  drop  or  two  of 
HN03  to  dissolve  the  residue.     Dissipate  the  uncom- 
bined  HN03  by  heating  on  a  water-bath.     When 
dry,  moisten  the  residue  with  1  or  2  drops  of  NH4OH, 
or  expose  it  to  the  vapor  of  NH3,  by  inverting  the 
capsule  over  a  bottle  containing  ammonia  water. 
A  purple-red  color  of  murexid  indicates  uric  acid. 

(b)  Silver  Carbonate  Test. — One  or  two  drops  of  silver 
nitrate  T.S.  are  dropped  upon  a  piece  of  white  filter- 
ing paper,  and  then  touched  with  the  urine  made 
alkaline   with  sodium  carbonate.    A   black   color 
appears  if  0.001  per  cent,  of  uric  acid  is  present. 

INORGANIC  CONSTITUENTS: 

182.  Chlorids. 

(a)  Acidify  with  HN03,   add  a  few  drops  of  AgN03 
T.S.    A  curdy  ppt.  indicates  chlorids. 

(b)  Quantitative  Estimation. — Dilute  10  mils  of  U  with 
40  mils  of  distilled  water,  add  10  drops  of  10% 
potassium-chromate  solution  (free  from  chlorids), 
and  from  a  burette  run  in  drop  by  drop  tenth  normal 
AgN03  solution,  until  a  permanent  reddish-brown 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    173 

color  of  silver  chromate  is  produced,  indicating  end- 

N 
reaction.    Each  mil  ^  AgN03  solution =0.005846 

gm.  of  chlorids,  calculated  to  NaCl. 
(c)  A  better  and  much  more  accurate  method  is  the 
Volhard's. 

Dilute  10  mils  of  urine  with  40  mils  of  distilled 

N 
water,  add  an  excess  (say  12  mils)  of  -^AgNOa  V.S., 

2  mils  of  strong  HNOs  and  2  mils  of  ammonio- 
ferric  sulfate  T.S.  (ferric  alum);  mix  well,  and 

N 
then  titrate  with  j^  KSCN  V.S.  until  a  permanent 

reddish  color  appears.  The  number  of  mils  of 
KSCN  solution  used,  are  deducted  from  the  quan- 
tity of  AgN03  V.S.  taken  and  the  difference  mul- 
tiplied by  .005846  or  by  .003546  gives  the  grammes, 
respectively,  of  the  NaCl  and  Cl  in  the  10  mils  of 
urine  taken  for  analysis. 

Assuming  that  5  mils  of  the  KSCN  V.S.  were 
required,  then  12  —5  =  7  mils. 

.005846X7  =  .040922  gm.  or  4.0922  gms.  in  1000 
mils. 

183.  Phosphates    (1.  Earthy). 

(a)  Add  to  5  mils  of  U  3  mils  of  NH4OH;  the  earthy 
phosphates  are  precipitated. 

These  may  be  separated  by  filtration,  dried  at 
a  low  heat,  and  weighed — if  required. 

(6)  (2.  Alkaline).  Approximate  Estimation. — Filter  out 
the  earthy  phosphates  as  precipitated  in  (a),  and  to 
the  filtrate  contained  in  a  test-tube  add  one-third  its 
own  volume  of  magnesia  mixture.  If  the  entire 
fluid  presents  a  cloudy  appearance  or  a  milkiness, 
the  alkaline  phosphates  are  normal.  If,  however,  a 
decided,  dense,  milk,  or  cream-like  precipitate  forms, 


174  QUALITATIVE  CHEMICAL  ANALYSIS. 

the  alkaline  phosphates  are  present  in  greater  than 
normal  quantities. 

If  the  fluid  is  but  very  slightly  cloudy,  transmit- 
ting light,  the  phosphates  are  present  in  less  than 
the  normal  quantities. 

(c)  For  a  more  accurate  method  of  estimating  phos- 
phates, see  U.  S.  P.  IX,  page  22. 

184.  Sulfates. — An  approximate  method  for  the  estimation  of 

sulfates  is  the  following:  To  6  mils  of  U  contained 
in  a  test-tube  add  8  drops  of  HC1;  the  mixture 
is  shaken  and  2  mils  of  BaCl2  added.  An  opaque 
milky  cloudiness  indicates  that  the  sulfates  are 
present  in  normal  quantity. 

If  the  opacity  is  intense,  the  whole  mixture  pre- 
senting a  creamy  appearance,  the  sulfates  are 
present  in  excess  above  the  normal  quantity. 

If  the  cloudiness  is  so  slight  as  to  transmit  light, 
the  quantity  of  sulfates  is  subnormal. 

185.  Microscopical  Examination. — Besides   the  chemical  ex- 
amination as  given  in  the  above  scheme,  a  microscopic  examina- 
tion of  the  sediment  should  likewise  be  made.     It  is  advisable  to 
centrifuge  the  urine.     The  more  important  constituents  revealed 
in  this  way  are  the  following : 

(a)  Epithelium,  whether  single  cells  or  squamous  masses 
are  present. 

(6)  Crystals  of  uric  acid,  triple  phosphates,  calcium  oxalate, 
cystin  plates,  etc. 

(c)  Amorphous    deposits     of     urates,     broken-up     cellular 
structures,  detritus,  etc. 

(d)  Blood,  discs  and  casts. 

(e)  Pus,  single  cells  and  sacs. 

(/)    Casts  (tube,  waxy,  hyaline,  granular,  epithelial,  etc.) 
(g)  Mucus,  cells  and  casts. 

Also,  Fungi,  Bacteria,  and  Spermatozoids  are  sometimes 
reported. 


QUALITATIVE   ANALYSIS  Of  ORGANIC  SUBSTANCES.    175 

1 86.  Report. — The  findings  of  a  urinalysis  may  be  reported 
according  to  the  following  scheme  used  by  the  author: 

New  York,      190. 

REPORT  ON  URANALYSIS. 

When  Received 

Dr Patient ; 

PHYSICAL  EXAMINATION. 

Odor  Color 

Spec.  Gravity  Reaction 

Appearance 

Sediment 

Quantity  passed  in  24  hours 

CHEMICAL  ANALYSIS. 
Albumin 
Sugar 
Urea 
Bile 

Acetone 
Indican 
Chlorids  * 
Phosphates  * 

MICROSCOPICAL  EXAMINATION 
Epithelium 
Crystals 

Amorphous  Deposits 
Blood 
Pus 
Casts 
Mucous 
Fungi 

Spermatozoa 
Bacteria 

Analyst. 

*  Chlorids  and  phosphates  are  usually  not  reported  unless  a  request  is 
made  for  the  same,  when  an  exact  quantitative  estimation  is  made. 


176 


QUALITATIVE  CHEMICAL  ANALYSIS. 


PREPARATION  OF  REAGENTS. 

Reagents  should  be  prepared  only  from  chemically  pure 
substances,  or,  better,  such  as  are  guaranteed  as  to  their  purity 
and  strength,  and  are  marketed  as  reagent  chemicals.  The 
success  of  the  analytic  operations  depends  very  largely  on  the 
purity  of  reagents. 

The  water  used  in  the  preparation  of  reagents  should  be 
freshly  distilled  and  tested  for  impurities. 

ACIDS. 

When  "  acids"  are  mentioned  in  the  text,  dilute  acids  are 
meant  unless  otherwise  specified. 

When  "  strong"  or  "  concentrated  "  acids  are  mentioned 
use  the  undiluted  acids  of  the  strength  specified  by  the  U.  S.  P. 


HC1, 

H2S04, 

HN03, 

Aqua  Regia  HN03, 


1  part  to  4  parts  H20  by  volume. 
1    M     ".4     "     H20  " 
1    "     "5    "     H20  " 

1    "     "  3     "     HC1   " 


SALTS. 

Parts 

by  Volume 

(NH4)2C03, 

1  part  to    4 

parts  H20,  add 

1  part  NH4OH, 

(NH4)2C204, 

1    "     "  25 

"     H20 

NH4C1, 

1    "     "  10 

"     H20 

KOH, 

1    "     "  10 

"     H20 

NaOH, 

1    "     "  10 

"     H20 

K2Cr04,    ' 

1    "     "  10 

"     H20 

K2Cr207, 

1    "     "  10 

"     H20 

K3Fe(CN)6, 

1    "     "  20 

"     H20 

K4Fe(CN)6, 

1    -     ««  20 

"     H20 

QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    177 


Na2C03, 

1 

part  to  10  parts  H20 

Na2HP04, 

1 

"      "  10     "     H20 

BaCl2, 

1 

"      "  10     "     H20 

HgCl2, 

1 

"      "  20     "     H20 

AgN03, 

1 

"      "  20     "     H20 

Pb(C2H302)2, 

1 

"      "  10     "     H20 

MgS04, 

1 

"      "  10     "     H20 

Co(N03)2, 

1 

"      "  10     "     H20 

(NH4)2Mo04, 

1 

"      "    3     "     NH4OH    (strong),    add   6 

parts  HN03(34%) 

KCN, 

1 

"      "  10      "     H20 

KI, 

1 

"      "    5     "     H20 

FeS04, 

3 

"      "90     "     add  H2S04  10  parts 

(NH4)2S04, 

1 

"      "  10     "    H20 

H2C4H4Oe, 

1 

"      "    3     "     H20 

Ba(OH)2, 

a 

saturated  solution 

BaS04, 

" 

U                            11 

CaS04, 

" 

"            " 

NaHC4H406, 

" 

((                          (I 

GASES. 

H2S. — Generate  the  gas  from  FeS  by  a  dilute  H2S04  (1  part 
acid  to  12  parts  water). 

NH4HS. — Pass  H2S  in  a  slow  current  into  some  pure  NH4OH 
until  the  latter  is  saturated.  This  solution  is  sometimes  called 
yellow  ammonium  sulfid. 

(NH4)2S  solution  is  made  by  mixing  3  parts  of  the  foregoing 
with  2  parts  of  ammonia-water. 

SPECIAL   REAGENTS. 

Alcohol— U.  S.  P.,  95%. 

Alphanaphthol. — 15  parts  to  100  parts  of  alcohol. 

Benedict's  Reagent  (Qualitative): 

Copper  sulfate  (pure,  crystallized) 17.3  gms. 

Sodium  or  potassium  citrate 173  gms. 


178  QUALITATIVE  CHEMICAL  ANALYSIS. 

Sodium  carbonate  (crystallized) 200  gms. 

Distilled  water  to  make 1000  mils. 

Dissolve  the  citrate  and  the  carbonate  in  about  200  mils  of  water 
with  the  aid  of  heat.  Filter  the  solution,  if  necessary,  and  place 
in  a  large  beaker  or  capsule.  Dissolve  the  copper  sulfate  in 
100  mils  of  water,  and  pour  this  solution  slowly  with  constant 
stirring  into  the  first  solution.  Cool  the  mixture  and  dilute  with 
distilled  water  to  1000  mils. 

Benedict's  Reagent  (Quantitative) : 

Copper  sulfate  (pure,  crystallized) 18  gms. 

Sodium  carbonate  (crystallized) '. . .  .200  gms. 

Sodium  or  potassium  citrate 200  gms. 

Potassium  sulfocyanate 125  gms. 

5%  potassium  ferrocyanid  solution ...       5  mils. 

Distilled  water  to  make 1000  mils. 

With  the  aid  of  heat  dissolve  the  carbonate  (half  the  amount 
of  anhydrous  salt  may  be  used),  citrate  and  sulfocyanate  in 
enough  distilled  water  to  make  about  800  mils,  filter  if  necessary. 
Dissolve  the  copper  in  about  100  mils  of  distilled  water,  and  pour 
this  solution  slowly  with  constant  stirring,  into  the  other  solution. 
Add  the  ferrocyanid  solution — cool  and  dilute  to  exactly  1000 
mils. 

Twenty-five  mils  of  this  reagent  are  reduced  by  0.05  gm.  of 
glucose. 

BROMIN  WATER. — Add  3  mils  of  Br  to  100  mils  of  water, 
agitate,  allow  to  stand  and  decant  for  use. 

DIAZO  REAGENT. — No.   I  sodium  nitrite   1   gm.    Distilled 
water  to  make  200  mils. 

No.  II.  Sulphanilic  acid,  5  gms. — Hydrochloric  acid  U.  S.  P. 
— 50  mils.     Distilled  water  to  make  1000  mils. 

The  solutions  should  be  mixed,  just  before  using,  in  the  pro- 
portion 1  part  of  No.  I  and  50  parts  of  No.  II. 

DIMETHYL- AMINOAZO-BENZENE. — 1  gm.  in  200  mils  alcohol. 
DRAGENDORFF'S    REAGENT. — 1.5  gm.   BiONOs,   boil  with 


QUALITATIVE  ANALYSIS  OF  ORGANIC  SUBSTANCES.    179 

20  mils  of  water,  add  7  gms.  KI,  shake  and  add  20  drops  of  dilute 
HC1. 

ESBACH'S  REAGENT. — 10  gms.  picric  acid,  20  gms.  citric 
acid  and  water  to  make  1000  mils. 

FEHLING'S  REAGENT. — No.  1.  Dissolve  34.66  gms.  of  care- 
fully selected,  small  crystals  of  cupric  sulfate  in  sufficient  dis- 
tilled water  to  make  500  mils  at  25°  C. 

No.  2.  Dissolve  173  gms.  of  crystallized  Rochelle  salt  and 
50  gms.  of  sodium  hydroxid  U.  S.  P.  in  sufficient  distilled  water 
to  make  500  mils  at  25°  C.  Keep  the  solutions  separately  in 
small  rubber-stoppered  bottles.  For  use,  mix  equal  volumes  of 
the  two  solutions  at  the  time  required. 

FROEHDE'S  REAGENT. — 1  gm.  sodium  molybdate  and  10 
mils  strong  sulfuric  acid. 

FUCHSIN-SULFUROUS  ACID  T.S. — To  a  solution  of  0.5  gm. 
of  fuchsin  and  9  gms.  of  sodium  bisulphite  in  500  mils  of  distilled 
water,  add  10  mils  of  strong  hydrochloric  acid.  Preserve  in  well- 
stoppered  bottles  protected  from  light. 

FUSING  MIXTURE. — 1  part  of  Na2C03  and  3  parts  of  KNOs. 

GUNZBERG'S  REAGENT. — 1  gm.  vanillin,  2  gm.  phluroglucin 
and  100  mils  of  alcohol. 

HAINE'S  SUGAR  REAGENT.  —  2  gms.  copper  sulfate  dis- 
olved  in  15  mils  of  water.  Add  15  mils  of  glycerin.  Mix  well 
and  add  150  mils  liquor  potassa  U.  S.  P. 

IODIN  SOLUTION. — 1  gm.  iodin,  3  gm.  potassium  iodid,  and 
50  mils  of  water. 

MAGNESIA  MIXTURE.— 5.5  gms.  magnesium  chlorid,  7  gms. 
ammonium  chlorid,  35  mils  ammonia  water,  and  water  to  make 
100  mils. 

MAYER'S  REAGENT. — 1.358  gms.  mercuric  chlorid  in  60  mils  of 
distilled  water,  add  5  gms.  of  potassium  iodid  in  10  mils  of  dis- 
tilled water.  Mix  the  two  solutions  and  add  enough  water  to 
make  100  mils. 


180  QUALITATIVE  CHEMICAL  ANALYSIS. 

MILLON'S  REAGENT. — 1  part  of  metallic  mercury  by  weight, 
and  2  parts  of  strong  nitric  acid  by  weight;  warm  gently  until 
all  of  the  mercury  is  dissolved,  and  then  dilute  with  6  parts  of 
water. 

NESSLER'S  REAGENT. — Dissolve  10  gms.  of  potassium  iodid 
in  10  mils  of  distilled  water  and  add  gradually  in  portions  a 
saturated  solution  of  mercuric  chlorid  with  constant  agitation 
until  a  slight  red  precipitate  remains  undissolved.  To  this  mix- 
ture add  30  gms.  of  potassium  hydroxid  and  when  solution  has 
taken  place,  1  mil  more  of  the  mercuric  chlorid  solution. 
Dilute  this  solution  with  distilled  water  to  make  200  mils.  Allow 
the  precipitate  to  subside,  and  draw  off  the  clear  fluid.  2  mils 
of  this  reagent  added  to  50  mils  of  distilled  water  containing  0.05 
milligram  produces  a  yellowish  brown  coloration. 

NYLANDER'S  REAGENT. — 4  gms.  Rochelle  salt,  2  gms.  bis- 
muth subnitrate  and  10  gms.  sodium  hydroxid  (dissolved  in  90 
mils  of  distilled  water).  Keep  in  amber-colored  vials. 

OBERMEYER'S  REAGENT. — 0.4  gm.  of  pure  ferric  chlorid 
are  dissolved  in  sufficient  pure,  strong  hydrochloric  acid  to  make 
100  mils. 

PICRIC  ACID  T.S.  (Trinitrophenol  T.S.)  C6H2(N02)30H.- 
Dissolve  1  gm.  of  picric  acid  in  100  miis  of  distilled  water  by  the 
aid  of  heat'. 

TANNIC  ACID  T.S. — Dissolve  1  gm.  of  tannic  acid  in  1  mil 
of  alcohol,  and  add  sufficient  distilled  water  to  measure  10  mils. 
Prepare  freshly  when  needed. 

TANRET'S  REAGENT. — No.  I.  1.35  gms.  of  mercuric  chlorid 
dissolved  in  30  mils  of  hot  water.  No.  II.  3.32  gms.  of  potas- 
sium iodid  dissolved  in  30  mils  of  water.  Mix  the  two  solutions. 
Add  20  mils  of  acetic  acid  and  make  up  to  100  mils  with  water. 


INDEX. 


Acetaldehyde,  147 
Acetanilid,  138 
Acetates,  114 
Acetic  acid,  114 
Acetic  ether,  149 
Acetone,  170 
Acetphenetidin,  139 
Acid  salt,  13 
Acid,  acetic,  114 

arsenic,  102 

arsenous,  103 

benzoic,  115-135 

boric,  99 

carbolic,  151 

carbonic,  91 

chromic,  103 

citric,  121 

gallic,  117 

hydriodic,  107 

hydrobromic,  107 

hydrochloric,  106 

hydrocyanic,  94 

hydrofluoric.  101 

hydrofluorsilicic,  97 

hydrosulfuric,  91 

hypophosphorous,  112 

lactic,  124 

malic,  123 

meconic,  118 

meta-phosphoric,  99 

nitric,  110 

nitrous,  110 

oleic,  124 

oxalic,  100 

phenic,  151 

phosphoric,  97 


Acid,  picric,  138 

picric,  T.  S.,  180 
pyrogallic,  117 
pyrophosphoric,  99 
salicylic,  116 
succinic,  118 
sulfuric,  97 
sulfurous,  92 
stearic,  125 
tannic,  117 
tannic,  T.  S.,  180 
tartaric,  122 
trichloracetic,  118 
uric,  172 
valerianic,  125 
valeric,  125 
Acid3,  preliminary  examination  of  the 

dry  substance,  89 
Group   A,  characteristic  tests 

of,  91 

Group  A,  chart  for  observa- 
tion of  the  reactions  of,  95 
chart  of;  89 
table  of,  87 
Group  B,   characteristic  tests 

of,  97 

chart    for    observa- 
tion of  reactions 
of,  105 
chart  of,  96 
table  of,  87 
Group  C,  characteristic     tests 

of,  106 

chart    for    observa- 
tion of  reactions 
of,  109 
181 


182 


INDEX. 


Acids,  preliminary  examination  of  the 
dry  substance — -continued 
Group  C,  chart  of,  106 

table  of,  87 
Group  D,  characteristic     tests 

of,  110 

chart    for    observa- 
tion    of     reac- 
tions of,  113 
table  of,  88 
Group  E,  characteristic     tests 

of,  114 

chart    for    observa- 
tion    of     reac- 
tions of,  119 
chart  of,  114 
table  of,  88 
Group  F,  characteristic     tests 

of,  121 

chart    for    observa- 
tion    of     reac- 
tions of,  123 
chart  of,  121 
table  of,  88 
Group  G,  characteristic    tests 

of,  124 

chart    for    observa- 
tion    of     reac- 
tions of,  126 
table  of,  88 
names  of,  13 

systematic  analysis  of,  88 
Table  of,  10 
Aconitine,  131 
Adhesion,  5 
Albumen,  163 
Alcohol,  143 
Alloys,  78 
Aloin,  134 
Aluminum,  50 
Ammonium,  70 
Amyl  alcohol,  150 
nitrite,  150 
Analysis,  dry  way,  18 

microscopical,  18 


Analysis,  polariscopic,  18 
qualitative,  17 
spectroscopic,  18 
wet  way,  18 
Anhydrid,  16 
Antimony,  37 

Reinch's  test  for,  36 
Antipyrine,  138 
Apomorphine,  132 
Aristol,  135 
Arsenates,  102 
Arsenic,  34 

acid,  102 

Bettendorff's  test,  36 
Fleitman's  test,  35 
Marsh's  test,  35 
Reinch's  test,  36 
U.  S.  P.  test,  36 
Arsenites,  103 
Arsenous  acid,  103 
salts,  34 
Atom,  2 

Atomic  weight,  5 
Atropine,  132 

Barium,  61 

Bases,  12 

Basic  salt,  13 

Benedict's  reagent,  qualitative,  177 

quantitative,  178 
Benzaldehyde,  150 
Benzene,  149 
Benzine,  149 
Benzoates,  115-135 
Benzoic  acid,  115-135 
Benzoic  aldehyde,  150 
Benzol,  149 
Benzcsulfmid;  139 
Betanaphthol,  142 
Bettendorff's  test  for  arsenic,  36 
Bicarbonates,  91 
Bile,  169 
Bismuth,  32 
Blood,  169 
Bonds,  5 


INDEX. 


183 


Borates,  99 
Boric  acid,  99 
Bromates,  111 
Bromids,  107 
Bromin  water,  178 
Brucine,  131 
Butyl  chloral,  135 

Cadmium,  33 
Caffeine,  132 
Calcium,  63 
Camphor,  136 

monobromated,  141 
Cane  sugar.  137 
Carbamid,  171 
Carbinol,  144 
Carbolates,  118 
Carbolic  acid,  151 
Carbon,  detection  of,  127 
Carbonates,  91 
Carbonic  acid,  91 

Chart,  for  the  comparative  observa- 
tion  of   the   reactions   of 
metals   with   three   com- 
monly used  reagents,  78 
for  comparison  of  phenol  and 

creosote,  151 

for  comparison  of  tannic,  gallic 
and  pyrogallic  acids,  117 
for  detection  and  separation 
of  a  mixture  of  five  groups 
of  metals,  83-86 
for  separation  of  alloys  and 

hard  metals,  78 
for    separation    of     insoluble 

phosphates,  75 

for   separation   of   a   solution 
into  groups  of  metals,  82 
showing  effect  of  group  rea- 
gents on  the  naetals,  23 
Chemical  change,  3 
Chemism,  4 

Chemistry,  definition  of,  3 
inorganic,  3 
organic,  3 


Chloral,  135 
Chloralamid,  140 
Chloralformamid,  140 
Chlorates,  111 
Chlorids,  107 

in  urine,  172 

Chlorin,  detection  of,  127 
Chloroform,  149 
Chromates,  104 
Chromic  acid,  103 
Chromium,  50 
Cinchonidin,  134 
Cinchonjn,  134 
Citrates,  121 
Citric  acid;  121 
Cobalt,  52 
Cocaine,  132 
Codeine,  132 
Cohesion,  5 
Compounds,  2-4 

classification  of,  12 
Copper,  32 
Creatinin,  170 
Creosote,  151 
Cyanids,  94 

Dextrin,  137 

Diazo  reagent,  178 

Diethyl  sulfondimethylmethane,  140 

Dimethyl-aminoazo-benzene,  178 

Double  salt,  13 

DragendorfPs  reagent,  178 

Elaterin,  134 
Elements,  2 
Equations,  12 
Esbach's  reagent,  179 
Ether,  148 

acetic,  149 

petroleum,  149 
Ethyl  acetate,  149 

alcohol,  143 

carbamate,  140 

oxid,  148 


184 


INDEX. 


Fehling's  reagent,  179 
Ferric  salts,  48 
Ferricyanids,  109 
Ferrocyanids,  108 
Ferrous  salts,  49 
Fleitman's  test,  35 
Fluorids,  101 
Fluorsilicates,  97 
Formaldehyd,  148 
Formalin,  148 
Formic  aldehyd,  148 
Formula,  11 
Froehde's  reagent,  179 
Fuchsin-sulfurous  acid,  179 
Fusel  oil,  150 
Fusing  mixture,  179 

Gallates,  117 
Gallic  acid,  117 
Glucose,  137 

in  urine,  164 
Glusidum,  139 
Glycerin,  152 

Glycerol  propenyl  alcohol,  152 
Grain  alcohol,  143 
Grape  sugar,  137 
Guaiacol,  142 

carbonate,  141 
Guaiacum,  138 
Gums,  137 
Giinzberg's  reagent,  179 

Haines  reagent,  179 
Hydriodic  acid,  107 
Hydrobromic  acid,  107 
Hydrochloric  acid,  106 
Hydrocyanic  acid,  94 
Hydrofluoric  acid,  101 
Hydrofluorsilicic  acid,  97 
Hydrogen,  detection  of,  127 
Hydrosulfuric  acid,  91 
Hypochlorites,  96 
Hypophosphites,  112 
Hypophosphorous  acid,  112 


lodates,  111 
lodids,  107 
Iodine  reagent,  179 
lodoform,  135 
lodol,  135 
Indican,  168 
Iron  salts,  48-49 

scaled  salts,  154 

Lactates,  124 
Lactic  acid,  124 
Lead,  24 
Lithium,  69 

Magnesia  mixture,  179 
Magnesium,  67 
Malates,  123 
Malic  acid,  123 
Manganese,  51 
Marsh  test,  35 
Mass,  2 

Matter,  continuity  of,  1 
Mayer's  reagent,  179 
Meconates,  118 
Meconic  acid,  118 
Menthol,  136 
Mercuric  salts,  31 
Mercurous  salts,  25 
Metals,  classification  of,  7 

Group  I:  comparative  obser- 
vation of  reac- 
tions of,  27 
Identification  in  a 
simple  salt,  28 
Notes    on    separa- 
tion of,  29 
Separation  of,  29 
Special  tests  for,  24 
Synopsis  of  separa- 
tion of,  28 

Group  II:  Comparative  ob- 
servation of 
reactions  cf, 
39-40 


INDEX. 


185 


Metals,  classification  of — Continued 
Group  II:  identification  in  a 
simple  salt,  41 
notes    on   separa- 
tion of,  45 
observations      on 
separation  of, 
44 

separation  of,  43 
special  tests  for,  30 
synopsis   of  sepa- 
ration, 42 

Group  III:  comparative  ob- 
servation of 
reactions  of, 
54-55 

identification  in  a 
simple  salt, 
56 

short  method  of 
separation  in 
a  simple  salt, 
57 

notes  on  separa- 
tion of,  60 
observations     on 
separation 
of,  59 

separation  of,  58 
special  tests  for. 

48 

synopsis  of  sepa- 
ration of,  57 

Group  IV:  comparative  ob- 
servations of 
reactions  of, 
64 

identification  in  a 
simple  salt, 
65 

notes  on   separa- 
tion of,  67 
observations      on 
separation  of, 
66 


Metals,  classification  of — Continued 
Group  IV:  separation  of,  66 
special   tests  for, 

61 

synopsis  of  sepa- 
ration, 65 

Group  V :  comparative  obser- 
vation of  reac- 
tions of,  71 
identification  in  a 
simple  salt,  72 
notes  on  separation 

of,  73 

observations  on 
separation  of, 
73 

separation  of,  73 
special  tests  for,  67 
synopsis  of  separa- 
tion, 72 
hard,  78 

separation  of  groups  of,  20 
table  of,  9 

Metaphosphoric  acid,  99 
Methyl  alcohol,  144 
Milk  sugar,  137 
Millon's  reagent,  180 
Mixture,  mechanical,  4 
Molecular  attraction,  4 

weight,  5 
Molecule,  2 
Morphine,  131 

Naphthalene,  139 
Naphthol,  142 
Nessler's  reagent,  180 
Nickel,  53 
Nitrates,  110 
Nitric  acid,  110 
Nitrites,  111 
Nitrobenzene,  153 
Ntirobenzol,  153 
Nitrous  acid,  110 
Nitrogen,  detection  of,  127 
Non-metals,  table  of,  8 


186 


INDEX. 


Normal  salt,  13 
Nylander's  reagent,  180 

ObermByer's  reagent,  180 
Oil  mirbane,  153 
Oleates,  124-136 
Oleic  acid,  124 
Oxalates,  100 
Oxalic  acid,  100 
Oxgall,  136 
Oxid,  16 

Paraldehyd,  148 
Peptones,  164 
Permanganates,  112 
Petroleum  ^ther,  149 
Phenacetin,  139 
Phenazonum,  138 
Phenic  acid,  151 
Phenol,  135-151 
Phenolates,  118-135 
Phenolsulfonates,  117-135 
Phenyldimethyliso-pyrazolon,  138 
Phenyl  salicylate,  142 
Phosphates,  97 

insoluble,  74 

in  urine,  173 
Phosphoric  acid,  97 
Phosphorus,  detection  of,  128 
Physical  change,  3 
Physostigmine,  131 
Picric  acid,  138 
Picric  acid  T.  S.,  180 
Potassium,  68 
Precipitate,  19 
Pyrogallates,  117 
Pyrogallic  acid,  117 
Pyrophosphoric  acid,  99 

Quantivalence,  5 
Quinidine,  133 
Quinine,  133 

Reagents,  18-176 

acid,  176 


Reagents,  confirmatory,  19 
gases,  177 
general,  18 
salts,  176 
separatory,  19 
special,  19-177 

Reinch's  test,  for  antimony,  36 
for  arsenic,  36 

Report  on  uranalysis,  175 

Resin..  138 

Resorcin,  141 

Resorcinol,  141 

Saccharin,  139 
Salicin,  134 
Salicylates,  116 
Salicylic  acid,  116 
Salol,  142 
Salts,  acid,  13 

basic,  13 

double,  13 

normal,  13 

names  of,  14 

scaled  iron,  154 
Santonin,  134 
Silica,  101 
Silicates,  102 
Silver,  25 
Soap,  136 
Sodium,  69 

Solubilities,  table  of,  81 
Stannic  salts,  37 
Stannous  salts,  38 
Starches,  137 
Stearates,  125-136 
Stearic  acid,  125 
Strontium,  62 
Strychnine,  132 
Succinates,  118 
Succinic  acid,  118 
Sugar,  cane,  137 

grape,  137 

milk,  137 
Sulfates,  97 

in  urine,  174 


INDEX. 


187 


Sulfids,  92 
Sulfites,  92 
Sulfocarbolates,  117 
Sulfocyanates,  108 
Sulfomethane,  140 
Sulfonal,  140 
Sulfonethylmethane,  140 
Sulfur,  detection  of,  128 
Sulfuric  acid,  97 
Sulfurous  acid,  92 
Symbols,  7 

importance  of,  10 
Synthesis,  17 

Table,  acids,  10 
metals,  9 
non-metals,  8 

Tannates,  117 

Tannic  acid,  117 

Tannic  acid  T.  S.,  180 

Tanret's  reagent,  180 

Tartaric  acid,  122 

Tartrates,  122 

Terpin  hydrate,  142 

Thiocyanates,  108 

Thiosulfates,  93 

Thymol,  136 

Tin,  37-38 

Trichloracetic  acid,  118 

Trichlormethane,  149 

Trinitrophenol  T.  S.,  180 

Trional,  140 

Uranalysis,  162 
Urea,  171 
Urethane,  140 


Uric  acid,  172 
Urine,  162 

acetone  in,  170 

albumen  in,  163 

bile  in,  169 

blood  in,  169 

carbamid  in,  171 

chlorids  in,  172 

creatinin  in,  170 

glucose  in,  164 

indican  in,  168 

microscopical  examination  of, 
174 

peptones  in,  164 

phosphates  in,  173 

report  on,  175 

sulfates  in,  174 

urea  in,  171 

uric  acid  in,  172 

Uroxanthine   indoxyl-potassium   sul- 
fate,  168     • 

Valence,  5 
Valerates,  125 
Valerianic  acid,  125 
Valeric  acid,  125 
Veratrine,  133 


Weights,  atomic,  5 

molecular,  5 
Wood  alcohol,  144 


Zinc,  51 


QD81 

S33 

1917 

ST. 


Schimpf,  ]         42221 
A  systematic  vourse  of 
qualitative  chemical  anal- 
ysis of  organic  and  inorgan 
ic  substances.^  3d  ed.... 


